I know, Keima is pretty crazy for Yokkyun. The teacher is partners with the little scientist, right? They must be a very strong pair. Also, I love Yui's goddes arc! Keima almost got captured himself! xD
...That sounds awesome! 8D I really hope that happens! It'll be an epic moment for him, and it'll show his character development! Great theory!
After all this is over, do you thing the devils will have to return? That'll be a sad parting for Elsie and Haqua.
It makes a lot of sense, really. If it's done well enough, it won't really seem like a cop-out. It's just that the girls have mostly gotten equal attention in the series, save for Elsie, Haqua, and Tenri, who show up more. Him not explicitly ending up with anyone could make sense.