Bith C'Baoth and Palpatine (and most EU Sith Lords) were stronger but not so much compared to their apprentices. Snoke was moving Rey and Kylo around like puppets with no effort. It's one of the many situations in the movie that were at odds with what was stablished.
Here are a few other things that made no sense:
- After Han's character assassination, came Luke's. The same guy that had hope for his, fallen to the dark side, father, didn't have so much for his nephew.
- Phasma is a very good, very wasted character. Fell to her pit of Carkoon pretty fast (they even stole the mask breaking moment from Asohka vs Vader Rebels scene).
- Is Benicio del Toro some sort of Lando?
- The entire movie is about letting go of the past...until they double back and say the jedi order will live through Rey.
- Yoda gives Luke a pep talk about teaching Rey about his successes and failures, to which he nods and...croaks before teaching any of that (I know, probable force ghost).
- Already told this in previous post, but they stablished ships cannot enter hyperspace with objects in front of them (like the Devastator entering the frail in Rogue One). But one movie later they seem to have forgotten.
- In Force Awakens, Luke's school was burned down by Kylo and the Knights of Ren (all geared with their KoR clothing and weapons). They seem to have forgotten that and now it's burned down by Ben (still not Kylo and using his blue saber) and some unspecified other students (that are supposed to be the other KoR, but before becoming that).
Rey is still a Mary Sue, but there's so much nonsense happening that it's almost unnoticeable.