Sony forced his hands in the sense that Raimi himself didn't feel the script was strong and his heart wasn't in it.
Other than that, I don't think they gave him unrealistic deadlines to make him quit. They wanted to get the film going regardless, since by the time he walked away , it'd been 4 years since SM3, and Raimi didn't feel comfortable moving forward based on the SM4 script.
They needed another film to get made as a way of holding onto the rights from what I recall.
So it wasn't as if they were doing things to push Raimi out the door, from their perspective.
Now of course, in Sony fashion, it backfired and ended making Raimi want to go. But ultimately, the preference was for a Spiderman 4 at that point, not a reboot.
As far as the "reboot script " goes, it was actually two scripts for two films which were new storylines for a potential 5 and 6, which were written in such a way that they could serve as a soft reboot if necessary.
I think it became a hard reboot once Raimi and Maguire left.