I also recently bought the pro version on Android (for the sync feature, I was already a longterm pro user on Windows before).
Having a start/stop tile on the watch would simplify the work flow considerably. I wouldn't even need to have a task picker but that would be nice, too.
I also saw that watchOS will get its version soon, so you obviously already have a concept of what to put on a watch version. I would be really nice to be on par with tge Apple ecosystem.