I really enjoyed Legend of Grimrock.
If you don't mind a suggestion, without spoilers, I'd suggest specialising each character as you won't have enough points to really multi-class. So for example don't give one guy both light and heavy armour or two weapon skills as you then won't max either and still end up only using one or the other.
Same thing with magic, may be tempting to have a mage learn Ice and Fire but would then probably end up being a master of none. (Ice is cool
)
Also try make the characters diverse/distinct from eachother. For example having two fighters both using axes and heavy armour could be a waste as you'd find weapons and armour that don't suit them and you wouldn't be able to equip them both with the best of those types of gear.
There's also some good and crazy user made dungeons. I think the "Master Quest" is one which changes up the original game so you can essentially replay the main game, but the puzzles and layout have been altered so you can rediscover and solve things all over. It also supports high lever characters for a NewGame+ situation. Some new stuff too I think.
Then you get crazy stuff like some dungeon that I think may have close to a hundred levels called Lord of Chaos, like I said crazy lol.