I'm okay with just about anything they choose to do in Spidey 4 as long as it's more like Spidey I & II than it is III. Lordy, Spidey III was a turd burger.
As for villains, I like 'em better when they're kept in the fantastic-yet-believable realm (well, "believable" in the Spider-verse, anyway). Doc Ock, Goblin, Sandman, they were fine, but Venom having the same origin as the Blob (the Sci-fi movie Blob, not Fred J. Dukes)? I know that's a riff the comic origin, but I think it might have played better in the movie if the symbiote was man-made science gone wrong (maybe a glitched experiment of Dr. Connors?).
I'm not sure he could carry the whole movie, but the take on Kraven from the Ultimate universe (reality TV star hunting Spidey) was pretty entertaining...maybe that could work? Though--with him probably not being a strong enough character to help carry the film--a second villain would be needed, and I think it hurts the film when they cram in too many baddies.
I know, I should be the villain in the next Spidey movie.
*punts Ms. Lion into traffic*
Haha, VENGEANCE IS MINE!