While i can't speak for the Divemistress, i think she wants to hear songs with life and energy. Stuff that doesn't put her to sleep, so to speak.
I try not to place any expectations on potential new material. I will probably appreciate it for what it's worth almost regardless of what it is. Like anybody, i'll be looking for that hook that grabs me instantneously from the first listen, but if it takes a few extra tries to get it, that's okay too
I know i recently started animating again, after about a two-year lapse. The first thing i'm doing is very short, something i figure most people will not see. After such a long break from each other, it's not hard to imagine them doing some "safe" recording to kick things off. Like a test song or a redone version-- something to spruce up a box set that's bound to have previously released stuff on it as well.