They might not be able to, I don't even know how the deal with Sony is but they were lucky to get Spider-man and a couple of his villains (Vulture, Mysterio.) For example, they can't use Venom because Sony is using him themselves, and Black Cat and Spider-Gwen are also franchises I heard Sony wanted to do themselves while having Spidey out on loan. I believe it was a 5 picture loan? Which would expire with this one. Did Disney extend that deal and we haven't heard? Odd MCU would invest so much time on making Spidey so important to their future without another deal in place to keep using him, I haven't heard anything from it.
On topic, this looks good. Mention of a multi-verse and introduction of the elementals of course sets up a lot of potential cool things. The thing people will most likely be looking forward to however, is Mysterio's role. Is he manipulating Fury? Or does he turn rogue halfway through the film? We all know he's the bad guy.
I'll be looking forward to the after credits scenes. They now have Fantastic Four and the X-Men to play with. Do they foreshadow the existence of mutants? Who's the next big bad, and if we get a glimpse, is it Galactus or Dr. Doom? I would do Dr. Doom first, and make Galactus the Thanos of the MCU 10 years down the line. Too soon to use Apocalyspe (though done proper, Apocalypse could be like Thanos), and they're sure as hell not introducing Phoenix without even doing their own version of the X-Men.