Would love to see some new characters and molds!
In my eyes I always see Pops that have the OG style with the squatting stance and/or no eyebrows are in desperate need of an upgrade/re-mold, and TMNT falls into that category.
Baxter and Casey are fine imo. No need to upgrade them. The original 2 waves however would look great with new action poses and accessories.
I'd personalty be happy with remolds of the Turtles, Splinter, Shredder, April, Rock Steady, Bebop and a Foot Soldier... But they definitely need to make Krang one way or another.
They did remolds of the old Ghostbusters Pops for the 35th anniversary, so why not TMNT too.