Depends on the subject at hand.

We can perfectly do without Point Allotment and Battle Leves.
Cross class abilities felt only somewhat good for crafting classes due to reinforcing the idea that these classes were interconnected. It wasn't so with battle classes, where it was a "level a class you don't care about to progress with the class you do care about". The only thing I ever liked about cross class abilities was classes having access to Eye for an Eye and Phsyics, which were not mandatory, but much appreciated for low level content (specially for squishies like THM). Overall, we can also do without battle cross-class.
Unnecesary MSQ quests could perfectly be turned into Sidequests, if programming allows it.

As for lost actions, with SCH I miss about 5-6 skills from old and Selene. So that's a point I agree on.