Breaking down doors. I really gets on my nerves, especially in Morrowind, when you get to a rickety old door consisting of 3 rotting wooden planks which you can't open because you don't have the key. There you are in full daedric armor and a weapon that can kill a Xivilai in one hit, but oh no, you can't just break down that door.
I do agree with previous posters that the freedom should return. While i do agree that NPC's should not be essential anymore, you should have more options to actually keep them alive. Unless you focus on restoration skills quite a bit you can't actually do anything to keep followers from dying - They need a big improvement in AI and maybe some more protection of their own.
BUT!
"Just because you can" is not an excuse to be able to kill important NPC's. There should be a consequence that is felt directly, not just a message saying that the quest has failed. I hated how you could kill important NPC's in Morrowind, but all you ever actually got from it was a message box stating you couldn't finish the main quest. Nothing else. If you want to kill an important NPC it should have direct consequences to your game. If all it does is take content away, why allow it? It only frustrates inexperienced players and gives nothing of value to experienced ones. For example, if you kill Martin in Oblivion before he lights the fires and fights Mehrunes, after a few game days or weeks the world of Tamriel should have changed to an Oblivion world. People would be in panic and you wouldn't be able to get the usual quests. Vendors would not be able to buy all your stuff or supply it because of the chaos in the world. If you still want to do it, you can, but you shouldn't expect the rest of the game world to go on like nothing has happened, which is what most people who want this 'freedom' seem to expect. But i guess most of them also only play the game with 100% chameleon.
Which is something that needs to be removed. Invisibility should not be perfect, it should be very expensive and not mask sound. There should also be magic that can detect invisibility. Same with chameleon. It should never be so that it makes you invulnerable. Same with reflect effects. Or resist. There's no fun if there's no challenge, otherwise you might aswell go around and using the kill console command on everything you see. It became an issue in Morrowind and a huge problem in Oblivion.
But i went off on a tangent.
Breaking down doors needs to come back.