Thor: Ragnarok director Taika Waititi has been quoted as saying the film, as it is being done under him, is going to do its best to 'ignore' the first two Thor films. While I can understand why he might want to go in that direction (namely to make up for why Portman's character and her wacky sidekicks are apparently going to be MIA), as long as it has Frigga staying dead, Odin's whereabouts from the last film being explained, Loki's continued liberty and presence in Asgard under disguise, and Thor's lack of desire to inherit the throne, those will be enough for me. All his other relationships like with Sif and the Warriors Three, even that of how he feels about Loki (if he finds out he's alive), can be flexible and I'd be cool with it. There has to be SOME continuity. Frankly I'll be glad if this is one of the few films that doesn't go down the road of trying to shoehorn in a love story. Or at least if it's not with someone who's not capable of standing in battle beside Thor, even if not at his level (like the aforementioned other Asgardians).
And there's talk of Spider-Man not being in Infinity War, at least not the first Phase 3 Avengers film. I can't imagine him being kept out of the conflict altogether, and since there was a report saying that none of the same heroes would appear in both films (except Hulk), that would make sense since Spidey would then logically only appear in Infinity War or the other untitled Avengers film. I really hope he gets the black costume in that case, since it's more likely that later Avengers film will take place more in outer space. It would also be a great excuse for them to put him up against the Doppelganger, a villain I would absolutely love to see brought to the big screen. Since I doubt he could defeat the beast just as is, he might need the alien symbiote in order to give him enough of an edge to compete with it. Plus if he's not in the same league as Hulk, Thor, Doctor Strange and Captain Marvel (or Scarlet Witch and Vision), the only way to really boost him up to an appropriate level without getting convoluted would be to do just that.