Man, I think rumble is a gimmick. (You can feel everything your character feels! As long as you pretend your character is unable to feel any sensation anywhere but his hands! COMPLETE REALISM FOR THE SUFFERERS OF SEVERE DISORDERS!) This is like a super ultra mega gimmick.
If only heat and cold were enough to let a blind person play, there would be blind players tournament around rumble controllers already. I know I said I don't like rumble in the previous sentence, but if you need to relay information to someone who can't see you can do a lot worse than an instant tactile sensation that can change duration or intensity. One of the ways you can do a lot worse is if you based it on something that cannot be perceived when it's subtle, can be painful when it's extreme, and may take a few seconds for the brain to understand.