I'm ready for Mysterio. Back just after ASM1 can come out, I had a whole idea about a trilogy that obviously isn't happening now, but he would still be a fun villain for the new series.
I thought that the Lizard was a good choice for movie 1 because he's a classic we hadn't seen yet and because they could link his and Spidey's origins together to create something interesting. I loved all the Oscorp stuff, it felt like it was setting up for a larger world and a larger plot with Norman.
For movie 2 I wanted Mysterio. I know that studios always want the sequel to be bigger with more action, so how do you do that without resorting to the old mistake of multiple villains? Mysterio. It's an excuse to do whatever you want. You want spider-man to fight a T-rex? Spider-man fights a T-rex. All bets are off with Mysterio. Keep hinting about Osborn, give some more tidbits, but don't blow your load just yet. Give Peter/Gwen's relationship more time to develop. Introduce JJJ as a side character, use Mysterio to frame Spidey for something that eternally pisses Jonah off.
And then how do you top that for movie 3? Emotionally. The third movie is where you reveal that Osborn has been pulling the strings the whole time. This is the movie where you reveal what happened to Peter's parents. And this is the movie where the Green Goblin finally shows up as the singular main villain and kills Gwen. It's the finale of this era of Spidey's life.
The villain of movie 4 could be Tobey Maguire because bringing him back is the reason Ben Reilly turned to dust.