Hatter and False Face appeared on a list a while back. We also never got a Bat-copter. We literally got every vehicle in the line, plus a bonus Jokermobile but no Bat-copter, so that will always gnaw at me. Wayne and Grayson can be customized thanks to the unmasked heads (unmasked Robin is still pricey but not $350-450 like he used to be...he's under $130 usually as of this post).
Toy Shiz says he was told at Toy Fair it's over due to likeness rights but there must have been plans given the names on the list. I don't really buy that given the existence of the $250 Joker playset with figures, but it's fine. A new Eli Wallach head could give us his version of Mr. Freeze. A new John Astin head could give us his Riddler and a new suited body with derby hat on a pre-existing Gorshin could give us his fancy formal version of Riddler. The 1978 animated Commissioner Gordon could give us the show's Gordon with a tweak or two to the '78 head. The same for Lee Meriwether's Catwoman. And of course with no Mad Hatter figure it just seems incomplete given he was one of the more high profile villains on that show. Lastly, they could have done the pilot version of Batman's suit and there's a Killer Moth that would have been silly but still worth including. Funko gave us the Eli Wallach Mr. Freeze and pilot Batman suit and Mezco gave us the formal, derby wearing Riddler in the 5-Points set, so there is precesdent there for these being made.