But high maintenance in the vanilla world, imo, means someone who is so self centered that they must be the center of attention and they're never satisfied when they get it. Sounds like the opposite of a sub to me.
It can be, but I would make that the definition of a "pain in the ass". "High maintenance" might be the pretty word that is used to cover up the gritting teeth.

I see it as a matter of patience. Committed couples eventually (maybe not right away) accept that the other person has certain qualities and quirks that, no matter how long you live together, no matter how much they challenge and irritate you, won't be something they can really improve, help or fix.

A physically high maintenance vanilla wife takes the 45 minutes to preen and fluff herself before going out, or she needs a great deal of foreplay and comfort for sex, or she is extremely picky with food, etc. Her husband sits patiently, accepting that this is his wife, he loves her, and these particular traits can be infuriating and endearing all at the same time. The maintenance is knowing when to be patient, when to reassure and when to push her ass out the door.

I am lumped in the other category of an emotionally high maintenance wife. I cannot fix my "brain chemistry" to rid me of certain "disorders"; the meds help, but I will always challenge the patience of my loved ones in this area. If I get out-of-control upset I can be talked down it just takes a little while, sometimes i need a smack in the head (figuaratively speaking) to "snap out of it" (for the moment) and sometimes my panic attacks need calm reassurance.

Make sense?