I kinda-sorta follow Rian's Twitter and there's a pocket of REALLY angry people just following him around complaining no matter what he says. The complaints boil down to 1) WHY KILL LUKE LOVE LUKE 2) GIRRRRLLLLLLSSSSSSSS. Both are problematic for their own reasons (#2 is easily understood), but #1 is the one that kind of bugs me. The entire saga has been intimating that The Magic Skywalkers are the key to everything, and has an uncomfortable air of "royal blood" to me. This is why I was worried that a less deft hand would make Rey part of the family (or of an existing one, Kenobi being the chief one speculated), keeping the entire fate of the galaxy in a tiny number of people. I try not to conflate with current events when dealing with space fiction, but the Venn diagram of people pissed about Luke and those that are into wearing ugly red hats is a circle.
I guess reason 3 is the now-deprecated Extended Universe. I can't say I've ever read any of it (there's SO MANY), but there's an entire complex mythology there that was discarded, and that pisses people off too. The other problem is that the video games have gone a wee tiny bit overboard
with what Jedi/Sith can do with the force. If I were to guess, I think the hate crowd would have liked to see Luke take the lightsaber, say, "Oh shit, they need me!" Then he gets in the Falcon, interposes it between the Resistance and the FO's fleets, climbs out the roof hatch (sure there's a roof hatch...now), and turns the entire fleet into recycling by waving his hands. Then they get onto the Raddus, he waves his hands again and all the women are pregnant, and then Kylo Ren shows up and they fight with electric penise--lightsabers--for a solid hour, give up realizing they're tied, shake hands