Here's an updated patch with Eli's comments addressed. Now, these new commands seem to have all the functionality of the existing *-region and *-word commands.
Is the "dwim" acronym well known enough as "Do What I Mean" that that it doesn't need to be included in the docstring? I can put it in if necessary, but it's somewhat awkward.
I'm fine putting these commands in Emacs, and waiting to see if people like them enough that it's worth changing the bindings. Is there any specific user feedback or data we'd be looking for to know if we want to change the bindings? Or is it more a concern of waiting to see if any bugs shake out?