I don’t have a solution, but it’s a nice problem to have! 
I’m really happy with my Apple Watch, so even though I know you don’t want that one, I have been surprised at how much I use it.
I especially like the DO button from IFTTT, so I’d look at compatability with that as a real plus, although not required.
As far as ST goes, the Samsung Gear S and the Apple Watch are the only official integrations right now. The Gear S is a really nice watch and does more standalone than the Apple Watch. I’d expect it to always be first for official integrations. (that’s Tizen, though, not android wear. Should work well with your phone though.)
There are also a couple of community member created Pebble watch apps, but I don’t know much about those except that they exist.
And a community created app for Android wear called CleverObjects. Again, I don’t know any more about it than that it exists.
More discussion of pebble and android watch apps here:
And a blog article on using IFTTT on an Android watch. @tgauchat this could connect to the ST IFTTT channel, right? (this is where we once again give SmartThings props for having an IFTTT channel. It opens up so many integrations. 
)