My own theory is you're thinking is probably right. She was annoyed that Gellar got all the attention, but...the show is called Buffy, the Vampire Slayer. Of course they're going to focus on Buffy.

Didn't Aly also have those American Pie (or whatever) movies, which I think means that in sheer box office grosses she may be the most successful BtVS cast member? She'd gotten that coveted last spot on in the cast credits that used to belong to ASH. etc. So - two queen bees, one hive? And BTW - I do NOT hate Aly at all; she's funny in interviews (as is Sarah - they're both pros at the game.) in fact I started watching HIMYM because of her (although I've stuck with it because of - pretty much every other cast member esp CS & NPH. After watching Buffy, seeing her performance as Lily is actually a come-down for me. Like, eh, ok, she has her moments of awesome here and there.)

It's the ensemble thing. It's an ensemble show! ...despite it focusing on one character and one actor handling the bulk of the promotion and workload.

*snort*