After the Ghostbusters, who else would you like to see BW do? I think they'd be the ideal company to do Jake and Ellwood and Axel Foley, iconic characters that HT would never touch.
Death Wish III Charles Bronson
Dirty Harry
Chuck Norris from Invadion USA
Stallone from Cobra
The Shadow is also an underrated character I would love to see in 1/6
If they ever got into video game characters, Adam Jensen from Deus Ex: Mankind Divided
In a similar vein to their collaboration with Damtoys, Starship Troopers, (Rico, Dizzy, Rasczak) or Edge of Tomorrow (Cruise, Blunt). They're both well known properties, but not considered mainstream enough for HT.
Yes to Dirty Harry, Travis Bickle, and at the very least, Quint from Jaws!
Would love to see somebody revisit the classic Universal Monsters, too. Love my Sideshow ones, but the outfits art sometimes lacking compared to today's standards.