Twinking does not all revolve around WSG.
What your asking is very subjective, but in my personal experience I started my 10 (warr in sig) a while back (wotlk) without WSG in mind at the time. The creation of your twink should not be based off of its class' performance in WSG. I find wpvp just as fun as wsg. However, when Cata came out, I realized what my twink could do and I think that it reached its peak in WSG then. I wont deny it, a lot of sentimental value is tied to Sponsor and is a large reason why I dont care about what others say on my performances in WSG with 19s (mind you, I topped DMG charts once in 10-19 game).
Now, I understand the current trend is to hate on 10 twinks since they're the weaker twinks of the 10-19 bracket. They are. But I don't care. I don't play my twink to be the best FOTM on my team. I get it that 10s are weaker, but it wont stop me, nor will it stop other 10s from playing WSG.
Take 20-29 twinks for example. There are tons of 20 twinks in that bracket (p2p with f2p restrictions), and they don't seem to bother anyone.
Level 10 twinks are just as part of this bracket as 19s are. Take a few moments to think about that.