I tried that three times and Finch's walking speed was still superior to the rest of my party.
Are you using the same saved game? The speeds will have been saved in that, along with everything else.
As I recall, with the amount of mods I have, installing or uninstalling any component took a really long time. This time, it didn't. Could there be something wrong?
Nope, sounds right to me. Let's say you had these mods installed, in this order:
1 Tutufix Core
2 Tutufix Walking Speeds
3 TutuTweaks Exotic Weapons
4 TutuTweaks Bags of Holding
Then you installed walking speeds, so mods 5, 4, 3, and then 2 were uninstalled. Mods 3, 4, and 5 were re-installed after that. Then you installed Walking Speeds over top, and now it has become five, while the others shuffle down again. Then upon uninstalling it, there's nothing overlapping, so it simply uninstalls itself and doesn't need to re-install anything.
I think perhaps I should make a thread detailing how WeiDU mods work, since I've been explaining this quite a lot lately.