I've lived through several different Bonds, Batmans, Supermans, and now Spidermans , and I've heard the same thing everytime from fans. You can't replace Brosnan, You can't replace Keaton, etc.
Fanboys and the GA do develop emotional attachments to certain actors and versions of franchises, but GA are alot more open to giving new actors a shot , like it or not. I've seen it happen plenty of times before.
Now whether the actor delivers or not or is accepted by the GA is a separate issue. Whether Sony fumbles again and miscasts the role remains to be seen.
The reality of the situation is Sony is gonna do what they wanna do , and I don't think the fanboys are gonna have much of a say on this one. If they replace the actor I don't doubt they'll be a fair amount of flaming, nerd rage, and calls for a boycott , but Sony will do it despite how upset fans are. I've seen studios do it before , and if anything , a little controversy means interest
in the whos who of casting and the next film.