Well, I honestly don't think anyone else is a great fit for her, and the one I hear most about is Rick. She's only alive because Merle became a slightly better person long before Rick made his impotent half-assed attempt at unpressing the button. And, hell, at least when Merle was going to give her to the Gov, he was doing it as an "honest" bad guy who just wanted to use her to get close to somebody he really hated and wanted to kill. Rick seriously had to think about whether or not it was cool to let somebody torture her to death just for that one millionth of one per cent chance that Lucy wouldn't pull the football out of the way this time.
So, Rick not only has way too slow a learning curve to make him worthy of Michonne, but even after she saved Andrea from zombies, saved Judith from starvation, told him where Glenn and Maggie were imprisoned, and protected Coral while Rick talked to CrazyMorgan all day, she was still relatively expendable.
No way in hell, after that shit, is Rick allowed to get with Michonne.