ToME: the Tales of Maj'Eyal

Before I find this out the hard way: are there particular classes/zones/difficulties which are ill-suited to the use of auto-explore?

I've just started a Shalore Archmage, and while she's only on Normal, I'd like to both avoid getting one-shotted and avoid wasting playing time unnecessarily.

Yes, definitely. I wouldn't use auto explore at all on Madness. Its quite dangerous on Insanity. And will probably get you killed once or twice on Nightmare.

However there are other concerns that can change this a lot. Cauterize prodigy can mean you may not feel too threatened by such stuff on NM. In general any class that has active defenses probably wants to use things like clairvoyance to prep for fights.

You will probably hear a lot of differing opinions here but auto explore has two problems:
1) if you are using auto-explore you are not using a Telepathy analog to leverage maximal game play. It can be very advantageous to sit around a corner and either use AOE's out of LOS or prep up and then bum rush something

2) you can get put into a deadly situation. The "one shot" thing is not something that happens exactly on NM and below. Rather you either run into multiple things with a lot of speed or you get debuffed to really slow speed and then get hit multiple times. Similarly it is also possible to auto explore into a situation that may not "one shot" you but is basically going to kill you. For example auto-exploring into two or three snake or bee rares with skirmisher classes and not having something to get out of that situation like target phase door. You may not get "one shotted" but you may have to flee and be unable to do so.

For the most part these things don't become truly common until Insane+. And to some extent on NM- things like Bone Shield or cauterize can make auto-explore safe enough. You will have to play around and see where you are comfortable, a lot of it is gameplay based and build based with a good deal of variance.

You have a shield rune, right? Set that to "Auto-use when enemies are visible" and it will go a long way towards keeping you safe while auto-exploring.

This is not optimal gameplay-you're removing a defensive option you might need later in the fight for the conveinence of auto-explore-but on normal dificulty, that shouldn't kill you too bad. I know I can't live without auto-explore (for now), so that's probably why I'm stuck on normal myself.

Generally, Auto-Explore is ill advised in situations where you run the risk of subsequently getting killed after immediately meeting an enemy. On higher difficulties there is more of a concern for this, but even on lower difficulties you want to watch out for that overpowered Unique or rare that could pop out at the wrong time.

For the most part, best advice would be to avoid auto-explore with your Shaloran Archmage in such places as the final dungeon, or where you know that there is already a dangerous enemies roaming around.

Unless you are playing on high difficulty levels or with a very fragile character, auto-explore is the best option.

On normal, I always autoexplore. On nightmare, I always autoexplore with anyone who has bone shield, second life, a good pile of HP, or cauterize. On insane, I autoexplore once I've used track to see if there are any really dangerous guys.