Thieves are great, and, good fun and all. My point is, thieves are the least needed class. Nalia works just fine for the most part, easily filling the role. Or Imoen. Depending on who I am bringing with me depends on if I memorize Knock or not. If I can bash the lock, so be it. If I have several mages, one of them memorizes a few Knocks. My Cleric's level 2 spell slots are as follows. Slow Poison, Flame Blade, Silence, Find Traps, Resist Fire. (Flame Blade is actually pretty handy for some situations)
I like thieves actually, Bounty Hunters being tops on my list. Assassins are fun. I like Bounty Hunters more from a roleplaying standpoint, although in BG an Assassin fits the bill as well. Swashies are fun, but, if I want to dual wield and make mass kills, I use a Blade