Agree with the op.
This was basically a hard reboot cause they couldn't or didn't want to continue the story from ROTJ properly and that includes both personal character stories as well as the political backdrop.
Of course it is tricky to dial back a perfect happy end. How do you keep the Spacenazis alive after the death of the Fuhrer?
It would have forced them to at least include Coruscant in some way which was probably off limits because of some highlevel "let's not use anything from the prequels" decision and an unfounded fear to not overcomplicate the mainstream audience brain with "trade taxation" or political shenanigans where people are arguing in the senate.
Thus, the political factions feel like reboot reinventions of what we had in ANH instead of logical continuation.
The First Order, according to TFA has been raising troopers from birth, so it must have existed for at least 22+ years before the events of TFA. TFA is 30 years after ROTJ.
So whatever happy end Luke, Leia and Han and the Rebel Alliance achieved, lasted for less than 5 years probably. If you count their misbehaving evil son, Leia and Han probably had like 3 years before everything went to shit.
And where are all the rebel alliance cap ships? Where is everything?
Apparently Mon Mothma, who seemed to lead the DSII assault briefing, ordered the "new" Republic to do a full de-militarization, but would that really include every Mon Calamari cruiser? Is this why Admiral "Its a trap" Ackbar is trapped on the rebooted overgrown temple Yavin IV rebe...resistance base?
Did we discuss yet why there are no B- or Y-Wings in the Starkiller base bombing run so the audience could easily get who is who? Tie Fighter BAD, X-Wing GOOD.
Why there are no capships around a 100x bigger, planet sized, gravity, snow, trees and atmosphere having Starkiller base and the number of Tie Fighters seem to be like 10?
Why Leia has no scene whatsoever with Chewie after their both partner in crime Han dies?
Why everyone knows everything about BB-8 and our two heroes after they are airborne with the Falcon for like 1 minute?
How the universe in TFA feels smaller than in the OT. Resistance + Leia arrive like 5 minutes after they are alarmed by a pirate cantina spy. How fast is Hyperspace in JJAbrams land? And if it is that fast and easy, why are there even people living on less lush worlds if it is a 5minute trip to get to a nice world?
And why can a fully formed Starkiller base be destroyed after a 2 minutes brainstorm session, a hint from a janitor and 8 X-Wings?
How Starkiller base can move around, or not? Do we know yet?
How it shoots? Through motherfrigging Hyperspace?!
How its beams can arc around?
And here is another nitpick that surely hasn't been discussed yet:
Why does Snoke's holo chamber walls have a rocky granite surface? That would not make sense on the SD Finalizer. So it must be on Starkiller base. If it is on Starkiller base. How fast can they move back and forth and how close must Starkiller base be to both Takodana, the Resistance base Yavin IV world, Jakku and those poor innocent Republic worlds that get blown up instead of something of importance?
Locations feel super close and stuff often vague probably a result of JJ's trademark pace and it hurts the world building.
EDIT: The answer to all this is that TFA is a script built around visual story telling and done so with a hot needle. Everything serves under the premise of where characters have to be at certain times for maximum impact or pace or easy understanding, but it is done so by sacrificing established universe rules or basic logic when they get in the way.