I don't know, Patrick Stewart's good, but he's missing something that, for example, the new BSG characters are infused with. The ability to act a part without it seeming like you're an actor playing the part. He had it at times, but even then...

Look at the scene in First Contact, when Picards has that hissy fit about stopping the Borg, and the line being drawn "heeah!" It's overacted - doesn't seem natural.
I dunno, perhaps it's just a matter of mismatching the actor to the character, but IMO Forbes is an excellent example of someone who infuses her character with her own personality, and comes across as "real" because of that.