Love most Secret Lairs, Team Headquarters, Hideouts, etc... a huge draw for most any line would always be the potential for those.
Joe's in most their incarnations always got one. Wish Mego had offered more, the Hall of Justice mentioned by the OP, and their Batcave could have been better executed.
Also wish they'd made a parallel one for Zorro, or added characters like Phantom (Skull Cave) , Shadow, Green Hornet, all with lairs.
Similar for Marvel U, the Avengers HQ, or Asgard. DC: Fortress of Solitude, a Titans lair, Themiscyra, Atlantis set, Rock of Eternity (yeah it's pretty much just a mountain cave with a throne and Statues, Some kind of Hawk-Lair/Weapons museum. An OA home-base with charging station Giant Battery, some kind of Flash Crime lab, and of course all the potential villain lairs. all these could have been great.
Especially scaled for the Super Powers line. I think there are a few un-produced art concepts out there.
Never had them but Thunder cats lair, and Greyskull were some great examples.
Wayne manor would only interest me if it's specifically attached too, or concealing a Batcave behind secret panels, or underneath, otherwise it's pretty much getting close to just a doll house.
Again
I get why a bank or museum and other city environments, would have more general use, but also a seem a bit generic.
I guess ideally for any good toy line there'd be some of both.