If I had a time machine and wanted to waste it on betting on things that don't matter, I'd bet my entire savings account that if you went back and made the lead up to 4e friendlier to people who loved 3.5 (ie, no making fun of it in official announcements and such), and presented powers in a way that looked more like abilities in Star Wars Saga Edition (like 5e has done), decreased the PHB number of powers in favor of including at least 1 of the PHB2 classes, released the rest of the PHB2 classes within the first year (and the gnome, for crying out loud), and tweaked some other presentation problems here and there, the edition war simply would not have happened. Full stop.