I liked that MJ finally admitted sometimes she did do some stupid things in the end - before that admission/fight with Peter, it seemed mostly 'Peter's fault', and she kept insisting that she didn't need to be saved, despite going into multiple life-threatening situations without any sort of defense until she picks up the stun gun in her last mission.
I could certainly see her point of view and being tired of Peter's split-focus and hero complex, but for a bit there it felt a little odd. That being said, I really liked the argument/section where you're playing as her directing Spidey where to go and who to take down during the train station.
OTOH, Miles felt a little weak as a sudden 'player character' addition - without having knowledge of ultimate Spider-Man, it would seem like he's a totally random dude who just happens to luck into Spider-powers.
Aunt May also felt a little bit weak - her death was well executed, in that Peter recognizes the needs of the countless New Yorkers versus being selfish, but it did feel like this particular Aunt May was a wee bit underutilized in the Peter/feast sections to make a 'huge' impact. BUT - I like the incidental 'NOPE' to One More Day.
Cameo/nod-wise, I liked the Eddie Brock fakeout with the garbage guy (unless his twitter name is false, the Eddie there has a different last name), the Raimi shoutout with the subway, and the animated suit being cel-shaded. Sable being the one person to enjoy the 'witticisms' was also nice, and the Mysterio fakeout during Halloween was also fun.
However, while I'm (trying) to not add to the 'controversy' around Black Cat into account, having the Black Cat section end up in a nothing-burger feels....not nearly as bad as the ME3 original 'buy our DLC' message, but does feel at least somewhat similar there.
As for the plot/sequel...given that Spidey already fought off Mr. Negative's 'mind control via angry emotions' attempt, I can't see the symbiote plotline working quite the same way - unless Miles somehow starts upstaging him, but that would ruin the buddy/mentor dynamic they'd presumably want to build there.
Harry looked briefly like he had tentacle hands, and JJ's son is already in outer space, so having it go to Harry, and/or Norman futzing about with it and fusing some of his lab-spiders to it and forming the symbiote would be possible - albeit that would maybe 'cheapen' the connection the symbiote/venom has to Spider-Man
(sidenote, I realize it's game-mechanics related, but I thought it interesting that, unless I'm remembering wrong, Scorpion in cutscenes doesn't set off the spidey-sense - such as when he slashes you with the poison - but in the battle with him and Rhino he does set it off)
Game-wise, I hope that the sequel has more 'build up' multi-tiered side missions that lead to a boss, a la Tombstone - and less of the 'overworld collectibles' without having a deeper connection/meaning to the story. If the stealth sections stay in.....I dunno. Maybe make it a little less insta-fail, and/or trial-and-error (in a few missions, not all of them)
I will eat my own ass if we get co-op
IMO It'll likely either be Miles off doing his own thing in side missions (maybe in a separate part of New York), having 'overlapping' investigations, and/or getting to pick one or the other character (either the whole game, or at times). I don't know how well co-op would work when the combat is more frenetic than Arkham's already.
Edit:
Goblin is definitely happening at some point - Norman has active research on how to duplicate spider-powers (the lab spiders AND his notes on the table), has 'homemade' grenades, and the mask - the question is whether it will be Norman or Harry as the Green Goblin, or whether some rando becomes the Hobgoblin.