Just as you have created the confirm delete (which I love) there should also be an option to confirm send. I can't tell you how many times I've accidentally sent an unfinished text.

Also...
While trying to delete a high number of messages (but not all) in one text thread, I can't find the option to select all? This way I can select all, and un-check the few that I want to keep.
I assume there is no option yet.
Thanks, Tom