Why would you ever want it?

Here's how it worked. When you got to 40, you trained it. It was a passive.

To use it, you had to run for 10 seconds, After 10 seconds, it kicked in. If you got hit at all, or even stopped for a moment, it stopped. If you were walking around an instance, you could go running off if you kept moving for more than 10 seconds. You could not control when it activated, you had to make sure you stopped every 9 seconds to keep it from activating.

It sucked, that's why they removed it.

I know how it worked. I've been around since classic, please don't flame without thinking.

1. The discussion is about the new races, goblin and worgen.
2. Worgen have a racial ability called "Running Wild" which allows them to move at mount speed without appearing to be on a mount.
3. Plainsrunning was a way for tauren to move at mount speed without appearing to be on a mount, although it was sadly cut from the game due to implementation problems.
4. The basic idea behind Running Wild and Plainsrunning is the same, but Running Wild hasn't had implementation problems.

Doesn't it logically follow that I'm talking about bringing back Plainsrunning in the Running Wild implementation format?

Kodo's are ugly, lumpy oxen. Mostly for bearing heavy loads and eating. The settlers never wanted to ride their oxen, why do I want to sit on an uglier version of one? (Sorry kodo lovers, I don't get it.)

No, it doesn't logically follow, because all you said was: "Still no Plainsrunning." The connections were in your head, but not in your words, and we're not mindreaders. :)