Yes, I wam afraid of losing a big pot with AA. In a cash game, I NEVER slow play aces and I'm willing to lose big pots but in a tournie I want to survive and I'm happy to take the blinds rather than find myself first to act on the flop which probably won't help me (only another ace really helps bullets and then the board is usually crippled) and may break me.
In a cash game for small blinds, I'm not going all-in pre-flop from utg.

In this case, I would also limp because the blinds aren't worth stealing. But what I wouldn't want to do is make a 3-4xBB raise because it doesn't achieve anything. If you narrow it down to one caller, great. They've got a hand, you've got it dominated. But on the flop, you're in the dark and it's going to be hard to know whether they've hit until they re-raise you all-in and you're committed to the pot and telling yourself how many outs you've got (not ideal in a tournie). If you don't get a call, you've not got any advantage and you've done nothing for your table image by making the standard raise. If you go all-in from utg, at least you're confusing people.
The main problem is the post-flop play but I don't trust myself enough to make a laydown that's going to save me in this situation and, I feel, nor should you.