Man do I love jumping on bandwagons.
So far I played: Ryoji, Anastasia, Switzerland, Black*Star, Jacqli, Hizumi, Rolo, Xion.
Kuuderes
I love characters who look cold and stuff, but actually have a good heart and care for people (even better if it's only certain close people they care for). Switzerland and Jacqli both fall under this category.
Troublemakers
This is pretty much self-explainatory. Characters who are always up to something or end up getting in troubles for a reason or another are fun to play! Ryoji, Anastasia, Black*Star and Hizumi fell under this category. To an extent, Jacqli does, too, but she's more of a troll who like to put other people in bad situations.
More than meets the eye
As stated above I love troublemakers! But they're even better if you eventually find out that they're not really just idiots, and that acting in a certain way might be a way to hide something else (their issues, their emotions and their real thoughts). Ryoji, Black*Star, Jacqli and Hizumi are examples.
Family Issues
Strong family bonds is something that I seriously like. If a character has a strong sibling or sibling-like relationship with someone, chances are I'm going to love them! I like complicated relationships more, but even nice ones are cute. Anastasia had some issues with Alexei but she loves her family-- and in Camp the whole situation with Nicolai was explored as well. Switzerland has Liechtenstein (and to some extent Austria), Jacqli has Shurelia, Rolo has Lelouch, and Xion has Roxas and Axel. Though for Xion they're more like best friends than siblings, they're also her family, in a way, which is why I'm counting her.
Should not exist
Characters whose existence is going to/causes chaos! destruction! and so on ping me hard. All the more so if people are out to get them/openly hate them. I like them having a ~*terrible fate*~. In varying degrees, this includes: Black*Star, Xion, Hizumi and Ryoji.
I'm putting Black*Star here for the whole Star clan/that period where he was in danger of walking the kishin path, and Xion for being what she is.
Ready to sacrifice themselves
Either for a cause they believe in, or for the people they love. Ryoji fits here for the choice he gave to the SEES people, Hizumi, Rolo and Xion for what they actually did end up doing.
I have a lot of other pings, but I'm getting too lazy to list them/they involve characters I actually haven't apped.