This is more of a Gameplay Forum post and it needs an answer from someone other than a heroimm.

Having said that, I personally I don't see any fault with how the current terrain system works as there will always be some element of game knowledge and experience involved in playing any class. There aren't too many types of terrain, or room affects, that negate assassin hiding and it isn't hard to figure them out.

If you contrast that with a ranger which has a fairly complex set of terrain rules and lots of subclass options, the necessity to see the terrain type becomes much more pressing.

(The only notable exception really is for thieves, which you have mentioned above.)

I was just attempting to reinforce some tips on surviving for the newer members of the community because I cut the advice short earlier on the Newbie Channel.