B-b-b-but those photos are so cute! All of them! At the moment, I'm considering switching to MitsuAi for the day... All of those drawings are just beautifully adorable... I've drawn my own Ai X Mitsuhiko drawing, it's AU, but it's still Ai X Mitsuhiko. And age doesn't matter. Haibara Ai is Haibara Ai, not Miyano Shiho. She has received the chance to start a new life, and the only thing that is ahead is intelligence and maturity. But Mitsuhiko is only going to gain in those places, and she'll still the same, growing up with him. She knows Conan won't be hers, so maybe, she'll spend more time with the kids who taught her what friendship really was. Mitsuhiko is a lot like Conan when he was truly a little kid, smart, witty, and funny. Perhaps her heart will change with the seasons, allowing her to realize to put her old life behind her entirely, and truly become Haibara Ai, change from the darkness to the light. (Black Organization->Darkness, Mitsuhiko-> light. He actually has the kanji for light in his name.) Little by little, maybe Mitsuhiko will get the bravery to confess to her directly, and one day, maybe she'll respond. Then she'll be truly free.
But what I'm really trying to say is that they are a cute couple that works.