I can literally write a book about what's not needed in this series. But such a list would contradict the attraction of the series. For example, Marriage is not needed, clutter isn't needed, houses aren't needed, crafting isn't needed, etc..
I agree. Nothing is "needed", but these games are about playing how you want and having a great deal of optional features to partake in. I hope that we get more skills in the next TES game, instead of the 12 or 15 we will likely get.
Heck, if current trends continue we will have 3 skills (stealth magic, combat) in TES IX.