I'll throw in a bigger mistake is leaving out the Osborns. Yeah, Norman an Harry dominated Raimi's movies, but to leave them out is to shoehorn them into one sequel. Introduce them in SM1 and then have Norman become GG leading to Gwen's death in one of the sequels happen naturally.
I dunno, there was just so much Osborn in the Raimi movies that I'd rather they just be left out for now. I feel like audiences would just be like "What, these guys AGAIN?" There are plenty of other characters to explore.