From what I've been hearing, they were planning on rebooting after Spidey 4, so there was already a screenplay ready to go. I love Raimi, but if his vision couldn't be achieved I think the best decision was made in scrapping #4, and just going forward with the reboot.
James Vanderbilt wrote the new script, and he's put together some decent stuff (wrote The Zodiac). Basically this reboot could be very good, or a trainwreck. Spidey was rebooted as 'Ultimate Spiderman' about a decade ago, and the Ultimate comic has easily been one the best Spidey comic, as well as one of the best ongoing comic series of the past decade. After 10 years, that book is still focusing on Peter is high school along with his relationships with Gwen, Mary Jane, and a bunch of others. If Ultimate Spiderman can be good, then there's no reason a new franchise can't be as well.
I think they'll cast an unknown as Peter, although Michael Cera is a name that keeps popping up (he's too old to play the part now). If they get a decent director and use the Ultimate comic as a model, we'll have a huge hit. If they're trying to go the whole Emo/Twilight route, then we're going to have a huge mess