From E_CHU_TA!...
Maybe, Hamill's push-back stems from his knowledge that Lucas had a better arc for Luke.If so, then that would be a sensible reaction.
I really did enjoy The Force Awakens, but I now see that it has some fatal flaws that were completely avoidable.
Their starting point did not have to be so explicitly aping the first film.
Would it have been "wrong" for the starting point of the new trilogy to be set in a galaxy in Balance? Did it have to start out being so deeply Dark-sided? What would a Balanced start look like? Who said that it would have to be "peaceful" as we imagine peace?
After all, a universe in Balance is
still a pretty terrible place to be! We're brainwashed not to contemplate Actual Reality because those In Charge want us to be as divorced from Natural Law as much as possible. The more they pervert the Rules, the more power they acquire, and it's far more efficient to trick their slaves into believing that they're free than to recruit and train a security force to bash heads in and store the rebels in extremely expensive buildings.
But let's pretend that there is no propaganda and no educational system to encircle our brains with their Matrix prison...
Is the universe, seen in its pristine and unfiltered state, splendid to live in?
No. Far from it. But at least it's then
Honest.
No matter how "softly" and "lovingly" a creature tries to live Life, there's one unavoidable law, in order to live one must destroy. Every creature MUST consume. There are
no exceptions. Every hardcore vegan wipes out an infinite list of future possibilities with every seed that's swallowed and destroyed.
However, the consumption of that seed, the absorption of its solar/plasma energy, allows the vegan to redirect its energy into a new set of infinite possibilities of their own choosing. Of course, there is still a very clear loser here; that seed-plant will never be able to direct its energy within its range of potentialities, it will never prosper and it will never produce progeny to carry on.
Nothing escapes this. Nothing.
To me, the breadth of storytelling potential is wide open here. Endlessly fascinating in its potential combinations.
But instead, we were given a Star Wars rehash, only magnified for the video game junkies. Snoke is more considerate, more intelligent, and more insidious than Sidious. His world-destroyer many multitudes of times better than the Death Star. The TIE Fighters are identical yet even better with their reversed
color schemes.

Rey makes Luke look like an absolute wimp. The list goes on and on...
The more I think about it, the more I wish that they would've tried something original that didn't challenge canonical foundations. Lucas himself said this.
I don't blame him.