I probably won't cosplay from it until I play the game, and I probably will pick a character based on personality, but for now, I will pay attention to characters whose costumes I like the most, merely because it'll help me to decide if I really do want to make the costume or not.
Some people pay attention to personalities, some people just like pretty costumes, and some people have at least a small care for both. It doesn't matter as long as you have fun.
Yazoo - FFVII:AC|| Yoruichi Shihouin - BLEACH||Radu Barvon - Trinity Blood
Sebastian Michaelis - Kuroshitsuji||Signum- Mahou Shoujo Lyrical Nanoha A's||Marluxia - Kingdom Hearts
Rinoa Heartilly - FFVIII||Marluxia - Kingdom Hearts||Suiseiseki - Rozen Maiden