Hybrids

[azrael]

I've always liked playing hybrid characters more than anything else. Versatility is really important to me, and I like classes that have it.

Why not have the option to mix classes? At character creation, allow the option of two classes to be chosen, with the change that their mastery of their respective class trees is reduced. This would keep things a little more balanced, and make single class characters still viable. Since each character still gets the same number of class and generic skill points per level, the person playing these characters have to be really picky about what to invest in- but some people like options .
I don't code, so I don't know how hard this would be for Dark God or someone else to do, but I hope that someone can take this on

[DasRunzen]

If you like to try normally impossible classes, like the Sling-wark (which works great btw) and just want to get talent trees that are not open on classes normally, i really recommend the infinite way mod.
It invalidates your game though, meaning you cant link things in chat and dont get into the charactervault, but everything else works fine in 40, even though the mod is made for 38.
And it really gives a nice touch to the invinite dungeon as you can actually use your gold there.

[Grey]

There are already designed hybrid-style classes in the game which are more balanced than what you suggest, and there are ways of experimenting and playing around with existing classes in weird ways that make them play differently.

[Mithril]

Interesting idea. Obviously this would enable various kinds of possible abuse but I guess that is part of the fun. In order to limit the powerfulness one could limit maximum level to 25 for each class (if playing two classes). Effects dependent on level would only be calculated using the appropriate class and not using the sum of levels. In order to not confuse new players it could only become available after winning the game.

[Planetus]

I think some of this is already achieved through the talent trees that can be unlocked by the escort quests. I'd like to see more of these, but we already have the Anorthil's healing tree, the Divination tree, Combat Training, Survival, the Sun Paladin's sun Chants, and the Alchemist's Staff Combat and Stone Alchemy trees available to classes that don't start with them. That means you could teach your Bulwark the Anorthil's healing spells for nice effect (though they wouldn't do much with low magic), or give your Necromancer the Alchemists Channel Staff (very nice, btw), or let your rogue infuse gems into armor, or whatever.

I'd love to see this system expanded. I'd also love to see the escorts be more survivable in higher-level dungeons.