Aside from the maquettes (which I passed on since I didn't discover them until after Batman had sold out), I think we have very similar Batman: The Animated Series collections. I collected everything I could find from the series, and still have it all (including that elusive Robin Dragster vehicle).
I even have a great cell from the show of Batman and Robin from "If You're So Smart, Why Aren't You Rich?"
But I disagree with you about Mattel being able to make a quality B:TAS figure. While they seem to have given up on 6 inch figures, I have no doubt they could do a quality line with this show, as I have the new Beware the Batman figure, and it's pretty cool. Nice articulation, but not too much to get in the way of the animated style.
The only problem is, they wouldn't offer the character selection that the line needs in order to outshine the Kenner series. Mattel would just make a wave similar to the '66 series, and then kill the line.
Anyway, I'd much rather see Hot Toys get the rights to the show and give us an amazing Batman and Joker if nothing else.