I didn't particularly like Seaver (had to Google the actress; I'm bad with names), but she was no more unrealistic than Reid. Don't get me wrong, I love Reid, but if we're gonna be throwing around the term "Mary Sue," then Reid definitely fits the bill.

Garcia is my favorite character in the series, but I think you're right that they treat her like a little kid sometimes. I like that she's quirky and weird and doesn't usually get too "Manic Pixie Dream Girl." (She's strange enough, but it doesn't function as ~inspiration~ for stodgy dudes.)

So, yeah. One of the reasons I ditched Law & Order: Special Victims Unit for Criminal Minds was for the ladies, but just because it's better (than a pretty low bar) doesn't mean they can't improve.