This is the one harem manga where I don't want a fixed ending. I really hope that while we do know that Fuutaro will choose one of the 5 at the end, the mangaka will leave who he chose up in the air.
Now, I know that this is far from the popular opinion, but for a story where every girl ( other than Itsuki) could have the been the no. 1 girl had she been in a different manga, I think having an ambiguous end and making the readers contemplate about Fuutaro's choice will leave a strong impact.