It's not that it relies on G4.
It's that it resorts to the "Happy ending was undone offscreen. So we're immediately back at square one, if not worse" cliche, which seems to be the best way to drive longtime fans away from a sequel these days.
The Beginning Of The End.
The most-controversial arc would be time-paradoxed away, and my ex-favorite villain would revert to my favorite (let-alone recognizable).
Given how controversial this Generation already is, for how it connects to G4 — if anything, I predict another Star Wars Sequel–type fiasco.
Which is tragic, since G5 is decent in isolation.
Some of mine are Link (the Legend Of Zelda show) Oogtar (the Super Mario World show), Dartz (Yu-Gi-Oh!), Bendy (Foster's Home For Imaginary Friends), and King Sombra (Season 9).
Pony Of Shadows. Too tell-don't-show as a threat.
S9 Sombra. Too in-name-only as a character.
(On the plus side — Stygian was decent, and I do like Alvin Sanders's other roles.)
Not just consuming it; Tirek actually used it. Remember when he snapped his fingers (like you-know-who), and summoned Twilight's friends in those orbs (something you-know-who can do)?
Speaking of Sombra, his S9 rewrite is this for me.
After all his caution and seriousness in S3, S5, and even the Comics - I'm supposed to believe that this campy, reckless strawman is the same character?