Try zoning.
I logged in with wild charge and without glyphed prowl.
I glyphed prowl and talented feline swiftness, but feline swiftness was only applying in caster form. The prowl glyphed worked, and I began prowling at 125% (I don't have the feral set bonus, or much feral gear at all).
I then zoned into Twilight Highlands. Now my cat form unstealthed is 144% and stealthed is 151% (night elf).
No clue what's going on. I'll also point out that this speed is faster than my rogue can achieves if she picks her tier 1 movement talent, which is like the druid one, but only applies to stealth- so expect some cross class QQ about this at some point too.
Historically, the boot enchant has not stacked with the "melee speed boost". The druid version of this is the cat form boost, not feline swiftness. The rogue version (now passive) is 15% movement, and it's that for a lot of classes.