Note: this is written with some early-game experience of the skirmisher, but I've not yet been past level 20ish with one. Insight from those who've taken one higher would be gratefully received. Also, this is about Normal difficulty. Higher difficulty levels change things, I know.
The skirmisher is a highly mobile, surprisingly durable ranged fighter Primary stats are dex (max first) and cunning (max second). Get as much con as you need to qualify for thick skin at a reasonable rate, and then split the rest between con and will, depending on whether you like hp or stamina more. Unless you're going for variant builds, you should be able to get enough str to qualify for your armor of choice from gear, and you shouldn't need magic at all.
Worth noting - the skirmisher does have a will-based tree, but it doesn't have any skills that are will-dependent, and you can qualify for the bits that you need over time with gear. Unless you decide that you really want antimagic, or pick up some cross-class skills by betraying escorts, the only thing you're really getting out of will long-term is the base stamina effects. Now, the skirmisher has some powers that are real stamina hogs, so that's not nothing, but it's not as much as a lot of other classes
Antimagic: Given what I've seen thus far, I don't advise it. It's tempting. It's very tempting. I'm quite fond of antimagic overall, the skirmisher can afford the generics, and they already have some build-in mobility options - making the lack of teleport runes less of a problem. Even better, they often want to invest at least a little in willpower to begin with. It's a trap, though - or at least looks to be one. As a skirmisher, you must have a sling, and you must have sling bullets, and the vast majority of your damage wil be channeled through both. Cutting off your arcane options for sling and stones *hurts*. A lot of your affixes are arcane, a lot of your *better* affixes are arcane, many of the uniques that you might find are arcane, and upgrades come along rarely enough that if you miss a tier jump because the gear was arcane, it might be a while before you get another shot. That's not to say that you *couldn't* play antimagic - just that it looks too costly to be worth it from my view.
Buckler training: A class-defining tree, and one of your sources of survivability. suggested 1/1or5/5/3-5
- Buckler Expertise: a one-point wonder that's also a one-point unlock. What's not to love? Given the way it scales, if you're maxing your cunning (which you absolutely should), then the impact of points past the first is going to be relatively low. Also, this is one of your two skills that's only applicable when you're in melee. Generally, melee is something that you want to be in briefly if at all, unless your foes are really just that nonthreatening - and if they're nonthreatening, then it doesn't really matter.
- Bash and Smash: a very nice little skill that should get its first point and stay on your skill bar forever. Early game, it's a knockback with some decent damage, which is nice for getting a bit of breathing room and/or juggling. Once you get 5 in Buckler mastery, the damage becomes *quite* nice, and it looks like having 5 here would be awesome for the second attack. It is, kind of - but it's also a trap. The problem is that Bash and Smash is melee-only. If you're looking at a foe that's powerful enough that you want to pull out your big damage-dealers on it, then you shouldn't be lookign for ways to get into melee. Bash and Smash is much better as a situational power than as part of your default plan.
- Buckler mastery: 5. Just 5. You like being in long-range. This power makes being at long range work better for you - and at 5, it also upgrades Bash and Smash, which is nice. I maxxed this as soon as it was available, and have never regretted it.
- Counter Shot: I'd sink a point or two here from time to time. There's no need to rush it, but it's nearly free damage - no stamina, and no actions. My suspicion is that at higher levels, it'll be worth maxxing.
Skirmisher-Slings: suggested 5/1-5/3-5/0or5
- Sling Supremacy: max this. Push every point you can into dex as fast as you can, so that you can max this faster. Hang onto dex-boosting gear in the early game even if it's not the gear you're wearing so you can swap it in for levelling and max this faster.
- Swift Shot: a decent little damage bump, and relatively cheap. Handy in places. Probably worth a point for the tactical applications, and might be worth maxxing eventually.
- Hurricane Shot: The closest thing you have to area effect. Useful, but kind of a resource hog-consuming a fair chunk of stamina and a *lot* of sling stones. Note that here, as elsewhere, if you don't have enough stones in the pouch, you lose shots. Worth taking to 3.
- Bombardment: expensive. It's a damage boot without a cooldown. That's nice. It's instant-on, instant-off - letting you use it when you need it, and not when you don't. *that*'s nice. It burns through both stamina and sling stones at a tremendous rate, though. It's a build choice in some ways. If you get it, you want 5 in it, and if you're spending 5 in it (and at least 3 in Hurricane shot) then you'll want to use it frequently, which means putting some real effort into building up your stamina economy and paying more attention to pouch size when selecting bullets (and current stones when fighting).
Tireless Combatant: the stamina economy tree. suggested 3-5/1/3-5/0-5
- Breathing Room: worth getting to 3 as soon as the willpower on your found gear permits. The built-in healing helps a fair bit early on, and the stamina recovery is about right for the early game. Later on, the healing is going to get less meaningful, so let the last two points be decided by your stamina needs.
- Pace Yourself: one point unlock. Never used. I suppose there might be builds where it would make sense to max this, but the global speed is pretty important. Is there anyone out there that's found a use for this one?
- Dauntless Challenger: Another stamina-and-hp regen skill, like Breathing Room, with the bonus that you are pretty much always getting the bonus from one or the other, and if you're doing it right you're often getting both. I'd take this one to 3 for the life regen, too. Beyond that, it's a matter of your stamina needs.
- The Eternal Warrior: look like it could be cool, but I haven't really gotten to the poitn where it's pertinent. Any comments?
Called Shots: efficient, effective single-target hits on a cooldown. Not sure of suggestions - suspect that it's 1/3-5/3-5/5. Particularly worth of note - not only do they skip right past intervening foes, they also travel instantly - making hitting mobile enemies from far away a lot more sure.
- kneecapper: A delightful little one-point-wonder. Early on, it's part of your kiting toolkit - keeping those melee foes far enough away for long enough to take them down. Later, that becomes somewhat less relevant, but it's still excellent for pinning the foe in optimal Kill Shot range and/or pinning them to the floor so that you can hit them with attacks that *aren't* called shots. Also serves usefully in getting that last bit of damage in on a high-value target who's behind a lot of enemies, and who you've *almost* killed with Kill Shot and Noggin Knocker. Might be worth upgrading later to get the pi to 2 turns if it's not enough for you at 1, but you won't get a whole lot of extra damage out of it.
- Kill Shot: So far, I haven't taken this above one point, and even so it's been a healthy block of damage when hitting things in its optimal range envelope. I expect that when I manage to shake lose the class points to max it it'll be quite the effective little damage-dealer.
- Head Knocker: This is our stun power, and it's a good one. Pick a foe anywhere on the board, hit them three times, and rack up a nice little stun effect. There is no excuse for not getting at least a point in this. Lately, I've been finding use in it as a fight-opener against major foes, and suspect I'll want to max it, but for now I only have two points.
- Sling Sniper: I haven't had enough experience with this one to give actual understanding of how good it is, but given how useful Called Shots have been with even relatively minimal investment, I suspect I'll want to max it. That phys pen sounds pretty tasty. I know I'll want at least three points for the cooldown help.
Trapping: honestly? no clue.
Poisons: Haven't used them myself. Vile Poisons looks interesting, but the fact that the 2nd and 3rd skills look like they're both melee range isn't really selling it to me. Anyone have any insight on this one?
Combat Training: you're here for Thick Skin and Accuracy, both of which you should max. Maybe take a point of armor training if you like your gloves and boots all clanky. Anything past that is the realm of strange variant builds.
Acrobatics: a *delightful* mobility tree. Vault starts as a kiting tool and winds up as your "get out of melee free" card. Tumble is a great little tactical repositioning power that you will just keep finding uses for (kite, insta-dodge ranged attacks, zip to where you can step out of site before the foe gets another turn, set up perfect range for Kill Shot... the list just keeps going on). For those two, the main benefit of more skill points is more range, and you should buy accordingly. Definitely worth more than one each, but may not be worth 5. Trained Reactions? I have a couple of points in it, and I use it, but I'm not sure exactly how much good it's doing me. Anyone else what to weigh in? I'm not sure about Superb Agility either - I'll likely max it, if only because I'm not particularly hungry for generics, and it sounds mildly useful, but feedback from others would be nice.
Survival. It's the survival tree. You all already know this one.
Field control: Haven't ever used this one. Given that I'm unlikely to go antimagic, I might wind up unlocking it just to have a place to spend points, but insight from others would be nice.
Races: eh??? I'll toss something in about races later.