This is the typical comic book fan question many ask. I like to think Wonder Woman is excluded only because she represents the middle ground between the two extreme. Some have asked whether people pick Batman because he's more relatable as a human that suffered loss or a wish fulfillment of being rich. Do I prefer Batman? Techically yes but it's more his mythos. I actually enjoy his family far more than him.
The Robins and Batgirls are closer to the audience than any of the Trinity. In the case of (most of ) the Robins (and pre-Flashpoint Cassandra Cain) their more than sidekicks their the heroes' kids either by blood or adoption. You don't really have that with Clark or Diana (with the exception of Chris Kent.) There's something very special these bat kids. Yes Bruce can be the biggest ass but there's something rather touching about him choosing them and building a surrogate family. Unless of course you read that as him putting together an army of disposable soldiers. (My dad was disturbed to learn how many their have been.)
So I guess what I'm saying is I'm more interested in Batman just because of the characters around him.