I'm using something similar to this for my Eclipse.

Keymap A does one thing.
Keymap B does one thing.

You can have the same Keymap A across a lot of toons.
And the same Keymap B across more toons.

Each toon (if you want to change independently) needs their own Keymap C.
Or if they will all change at once, then they can share a Keymap C.

Keymap C has two steps.
On Step one, it enables Keymap A for toon A (or group A) etc. and disables Keymap B for the same toon/group.
On Step two it does the reverse.

Two steps, one for on and another for off, seems to be much more reliable then a toggle.

If a keymap loads but doesn't do anything, I'd guess the keybinds are in conflict with something in wow.