you are stealing off bad people< think Robin Hood style
Doesn't matter. Stealing is stealing. Period. My characters (even the evil ones) DO NOT STEAL (unless, of course they're a thief character and belong to the TG).
Murder: Cool! All in a days work. Looting dead bodies: Cool! A great way to make some extra cash. Stealing: Not in this lifetime bub. Somebody worked for that stuff and I have absolutely no right to take it away from them (and yes, before you say something, even if they stole it from someone else, they still had to go through the work of stealing it in the first place.
As to the lock-picking, I usually play good characters as well (although they are really murderous thugs that prey on the baddies!). I really don't see it as an issue. Do you consider the Locksmith a criminal? How else are you going to satisfy your curiousity about those locked chests and doors in those abandoned places. I draw the line at breaking and entering and will not do it to the living (example: in Falkreath the Old Coot/Old Jarl wants me to break in to Hod's house and steal a letter. No can do. I like Hod and have no right to do that for anyone. Besides, if Beth had thought about it, they should have put an option in where I could just ask him about it. He probably would have answered honestly. That's the way he is!). (Another example: Morthal - trying to get at the lady vampire's journal. Supposed to break in to her home. No way! It's easier just to kill her boyfriend discretely and take his key. That way you're not breaking and entering, you have the key).