Early Act 1 is supposed to be easy / easier. You might want to continue playing a bit before renderering such judgement ("gamebreaking"). For example, thieving only works once per PC-thief/NPC, that means that yes, it can be an early boost, but such gear upgrades are one-time only (unless you exploit, but then you only have yourself to blame for breaking your game). In fact, I'm of the opinion that yes, thieving is broken, but broken as in "not worth the precious skillpoints", not as in "OP".
It's incredibly game breaking for someone that doesn't want to steal, the advantage you get seems insurmountable, I shouldn't need to steal, but that's all anyone gives you for advice on how to get gear or money.