No, there's been no teaser, though it has been talked about enough that YoshiP is aware of it due to interviews and so on.

My desire for Chemist is that I do not want a reskinned CNJ(hi Geomancer) and want something fresh, new and DIFFERENT for Healers as a Healer main. We've had to wait and I'd really REALLY like for it to be worth it.

I also want the Chemist to use a gun because... then the Trifecta would be COMPLETE. Gun Tank, Gun DPS and Gun Healer. (That and I'd love to shoot people healthy so so badly... it would help the levels of salt I have acquired over the years as a healer. Just... please.)