In a way, auto-climb did get slower. Instead of nerfing the actual speed of climbing, sprinting basically became the new speed for simple travel (such as from spawn to the front line). While the relative speed for climbing did get reduced, it kind of missed the point of slowing the game pace down to promote building. Even if this does make creating roads, tunnels and bridges somewhat useful, this isn't happening as a good lot of people still can't or don't use sprint properly from my experience. Combine this with the fact that faster gameplay just encourages people to focus on running & gunning, they don't just have the incentive to build such things.
I.e. not nerfd, nerf climb plese