you love shammy's.. i assume you have one on horde side then?
well then you must know the class a bit, and that should help you lvl faster..
i have a lvl 80 draenei shammy myself, and started a tauren shammy just for fun, seeing things from another end, doing different quests in different zones.. don't play it alot though..
but anyway, yea its worth to try it atleast.
no one is forcing you to lvl a toon to 80 i assume, so if you don't like it.. you can always leave it, or even delete it..
in short:
just go for it, and see if you find it worth the time..
no one can say that for you..