I think there was never a Gnome hate. The problem was there was no real Gnome love. Sure, there are some people that play them and want them back as Player Race for 4E now. But most of the people just never cared for them.
I can remember one Gnome character in 8 years of 3E. I also distinctively remember only one Gnome NPC I created myself, and I mostly used Gnome because I wanted a psionic psychopath and found that Gnome would be the most disconcerting.
Gnomes had also the problems of having no class abilities that made them stand out. The Halfling seemed more fitting into the "small race" role. He had racial abilities that fit the idea of a small creature far better - +2 to Dex, bonus on Move Silently. The Gnome was a smaller Dwarf by comparison, and thus he lacked a role.
The 4E Gnome isn't bad and seems to have found a niche, but is he player material? With their reactive invisibility feature, they seem like creatures that exist in hiding, not as members of adventuring parties or presence in typical settlements.