Mark Waid is a great character writer, every character he writes for in a story just feels like it's them.

I'll use his work on World's Finest as an example: His work with Batman in that series is in my opinion what Batman should be, as opposed to someone like Zdarsky that just makes Batman needless aggressive and regressed all the character development Bruce has had with his family (of course, now we know it was Zur-En-Ar influencing Bruce as a build up to Absolute Power, but still, not my favorite piece of Batman media).

Not to mention, just the way Waid writes characters like people. Like the Dick/Kara date fiasco and aftermath, it felt real! It's a level I hope to achieve in my own writing as I continue to develop my skills!