One big advantage that this new series has over the previous trilogy is how they are able to plan for future movies. They're setting up a larger universe and they can plot out the entire thing now as opposed to how Raimi and co had to deal with things. For Raimi there was never a plan-ahead type construction to the movies at least not for SM1. I don't think Sony had enough faith in the product to allow that to happen. It was more like, let's see how well this first one does and we'll take it step by step. I can understand that line of thought seeing as how superhero movies weren't really as popular as they are now. Both the Superman and Batman franchises had flamed out. It was the start of something new.
IMO that was something that hindered the ability of the previous trilogy to grow and expand and so by the time they got to SM3, it was prob tough to draw up something inspired. Again, imo, it looked like they tried for 'bigger is better' with the movie and tried to throw too much into the pot. The multiple villains weren't really the issue for the downfall of the movie yet I think people tend to associate the crowding of the movie as the main fault because it's such an easy thing to see. Without much analyzing you can look at SM3 and say, well it just had too much going on at once and there wasn't enough time to have all those characters make an impact. I think had Raimi had the ability to plan ahead for these movies, SM3 could have been much better. Smaller introductions of the villains in SM2 or even SM1 for that matter and then you wouldn't have the problem of multiple villains in the same way SM3 ended up. And being able to plan ahead for the remaining movies in that trilogy would have opened up the possibility of telling a different story or stories with more room to create.
That's how ASM2 is ahead of the curve so to speak and if they are planning this out properly we'll see this develop nicely. Because of the whole multiple villain angle and how people tend to associate with them as a result of SM3, we get these negative remarks and complaints. It's just an easy thing to see on a superficial level.