We thought the same thing about the maid AI, and totally plan to have multiple "levels" of affection.  You can see a little bit of it in effect now with the affection bar by feeding your maid when she's hungry.  These are really new additions, so you'll have to let Mai run for a while to see her hunger go up.  The bars are Hunger, Affection, and Stamina from top to bottom.  We'll be sure to add this to the description/documentation so it's clear!