Gonna be hard giving Cordelia to another man this playthrough ;_;
I'd pair her up with Chrom if the game actually allowed that. As it stands, Frederick makes for a decent enough partner.
More on the current thread of discussion, there's quite a few characters that I don't care much for. That I left behind most of the first generation as soon as I got their kids was a sad reality, although easy to justify given how far above their parents they were. I dropped my Cavaliers about as soon as the game would allow me. I stacked my army with Pegasus Knights, which cost me some stages, but after a bit of time they turned into literal engines of destruction, so I don't really regret that.
I really didn't care for Kellam. He was pretty boring, and just looked really out of place. His gimmick that he's never noticed worked pretty well for me, given where he stood in my army.
Most of the other units, I tried to give a fair shake, mostly for supports, although there's definitely a few that I completely skipped over. Ricken, for one. I didn't really use Maribelle either - by the time I got her, Lissa had assumed a role in my army as designated healer, and she was much better at it (and, quite frankly, much hardier) than Maribelle was. It helps that I wasn't that enthralled with her character, although her support with Donnel is fairly charming. Libra, I wound up forgetting about entirely after I got him. I only wound up using him because I was fast running out of bachelors and Olivia needed someone to pair with.
I actually liked Say'ri quite a bit - she had killer character design and Swordmaster is my favourite class in the game, although her Avatar support seems pretty boring, so I don't feel too bad about committing way before hand.
I didn't care much for Panne's kid at all. I always thought it was a bit funny, really, how Lon'qu and Panne managed to produce a wimp like him.