Without a high enough perception you will probably miss some things, but they are not essential, and there may be alternate ways to do the same things (ie perception can just indicate a shortcut, or give some extra loot). There are potions and skills which give temporary perception boosts, as well as equipment bonuses.
There isn't really a reason to disarm traps, as opposed to using a ranged attack to trigger them, and as Mental Poison said you can use magic or brute force on many doors/chests that you don't have the key for. The basic sneak will be good enough for the start of the game (you can boost it later if you find it useful for your builds or tactics), and there are teleportation and invisibility skills which overlap in most of the sneak functionality (you need to sneak to pickpocket, though that probably isn't a concern if you don't want to sneak in the first place).
Stealing is fairly easy, even without boosting any scoundrel type skills.
