Your comments

@ClarkHaynes This doesn’t  do what the original poster asks for, which is automatic hard-wrapping without manually requesting it by pressing a key sequence.

I’d really love to see automatic hard-wrapping. 

Vim is the only editor on the Mac which currently does this. Automatic hard-wrapping is really nice for LaTeX documents for the reasons that the original poster gives.
This would be fabulous. I’d love to use ST2 to compose my emails.
I agree with this! 

It would be even better if ST make use of the OS X Spell checking service, since it seems to do a much better job: e.g. handling capitalisation, plurals, etc.