For quite a while now, Textra has been leading the pack on the UI front as far as SMS apps are concerned (as your app description on the play store boldly reiterates). But with Google Messenger, what will soon be a stock app is beginning to get ahead of the curve. And one of their most impressive features is the recently added Quick Reply interface. It looks great, is very snappy and does not remain open in the multi-tasking menu like Textra's Quick Reply window often does.

IMO this is something Textra should definitely replicate (albeit consistent with its own style) to keep its nose ahead in the UI race.