I can clearly see that Aoi likes Oga and that Oga and Hilda might start to warm up to each other... But would romance ruin the whole comedy fighting?
well there will be no romance but i think and hope that at least at the end or so he will show affection towards hilda and hilda towards oga
so that we know "aha! he loves her and she loves him" without romance and that in the future (which wont be shown since beelzebub ends before that) that and that will happen ^^
something like that .. i hope
Romance now? Naw. In the end? Sure. I can totally see a few month timeskip where Hilda and Beel still living Oga and his family. Hell let's a throw in a actual pregnant Hilda still bickering with her not even going to married Oga as always, while Beel is happy to know he'll get a baby bro/sis, while his first words are; "shit, f**k*, hell no, and stupid Furuichi~! I can see that happen. Oh and Lamia actually looked like her mom and Furuichi and her are trying to confess each other their feelings, but she is being cock blocked by Alandelon. I can see this happen ~les gens~!