I am a massive fan of this show. It got me into comics. I watched it through my childhood and have revisited it a few times as an adult. I think it holds up, but part of that could be nostalgia talking. Objectively speaking though I think the voice acting is largely very well done and the plotting is about as sophisticated as a show ostensibly aimed at children can possibly be. Where it falls down is the character designs and some of the animation.
I would love to see a revival. As others have noted, the show ended on a cliffhanger and there are lots of unresolved questions from its final few series. I think it would be a mistake to focus on Spider-Verse stuff, as most of the final season was team ups and extra terrestrial, multiversal adventures. Let's leave that alone for a little while.
Given the choice, I think one final season would be all that would be needed to wrap things up and give the show a proper conclusion. Any longer and there would be a risk of ruining the shows legacy. There would plenty of ground to cover.
- Finding Mary Jane and the probable return of Norman Osborn
- The clone saga tease with Miles Warren at the end of the Hydro Man arc
- Another arc with Venom and Carnage (who were both underused)
- I'm not a massive fan of team ups but an appearance from the FF would be fun and would be an obvious opportunity to introduce the Sandman
- The Haunting of Mary-Jane Watson two parter did some interesting stuff with Mysterio that I think it would be worth following up on. He was also quite an underused villain on the whole.
- Hobgoblin was such a great villain and so well voiced by Mark Hammill that it would be a shame not to see him return.
I think, hypothetically speaking, that whoever was involved creatively would do well to steer clear of Kingpin, Doc Ock and Morbius, who were all pretty overused by the end.
On the subject of creatives, I would be baffled if Semper wasn't involved. The show was his baby and it would strike me as pretty pointless to bring it back without him at the helm (or at least present in some capacity.)