1. Doesn't really bother me as I rarely play a mage. We've lost a few spells, but at the same time, I feel like there is already a good selection of spells available (at least whenever I browse spellbook merchants, there seems to be a lot of options).
2. I've used the spell creator in both Morrowind and Oblivion, while it was fun, I don't miss it at all. Aside from destruction being underpowered at higher levels and a smaller variety of spells, I quite like the mechanics of Skyrim's magic system.
3. The breeding methods of Argonians is the last thing on my mind.

4. Essential NPCs are needed, so the devs don't have to deal with "Oh, I can't do X quest." "Its because you killed X person" "Well why did you make him killable??" type situations. Not really sure why the camp leaders are essential though, they don't do anything (I guess they may in the future).
5. I do agree with this, but at the same time, if you don't fast travel much, you'll encounter far fewer dragons.
Skyrim has its flaws, but for me anyway, it has been a vast improvement over Oblivion.