I'd skip the bunker. It didn't cut it in the late 90's. They've have to up its size and put somethig on the inside.
New speeder bikes might be nice, as in NEW. I dislike the Clone Wars speeder bike mold with it's sagging soft plastic front end. The one with the At-At can even sit on the ground well, which the Kenner one from 27 years ago could do. And I actually did like the exploding feature, even if it occassionaly activated when you didn't want it to.
Here's what I'd probably dig seeing...
Attack On Endor:
-2 Scout Troopers w/removable helmets... Use the Nik Sant sculpt but generic headsculpts.
-1 of the following... Either a Black Tuniced Imperial Officer utilizing most of the AT-AT Commander Sculpt with a hat and Needa "skirt", another AT-ST Pilot with perhaps fixed goggles that fit over the helmet, or a Death Star Trooper in the jumpsuit as they appeared on Endor. I'd probably dig the AT-ST Pilot the most.
-2 NEW Speederbikes... I agree, the current ones suck, and I mentioned to Hasbro eons ago in the Q&A that it'd be be neat to see it sculpted small, sturdy, and with a clear stand so it appears to float, sort of like the STAP comes with. They were receptive to the resculpts all that time ago, but it hasn't happened. I hope it does soon though. Part of me thinks the new Luke has the ball-jointed hips to ride a new bike a little bit better.
-Endor Logs or some of the outside eqipment seen around the Bunker would be cool. There are a couple things laying around on the ground , but anything like that to "beef up" the set would be great.
Defense on Endor:
-Nik Sant... Using the new Endor Commando body and a new vest and head, I'd love to see that figure re-puposed as Nik Sant.
-Generic Endor Rebel... Using the same vest and a generic headsculpt, voila, instant generic vested Endor Rebel.
-2 Ewoks... The two who narf the AT-ST are ideal.
-Catapult (or other Ewok trap/weapon, if they can do it).
-Properly Scaled Bunker Doors/front... I don't care if the interior is plain and hollow like the Hoth tower is, I just would like it if the doors could slide open (both sets would be cool), and that it's scaled right. Anything less like the POTF2 one is disappointing to me because it's tiny. It looks kind of goofy, like the POTF2 Hoth Tower looked too.
The Imperial Attack set would definitely need more than just two speederbikes though, but I think if they included that outside gear, it'd be pretty neat.
And I'd rebuy those speederbikes if they made one with Luke, one with Leia, and a single with a biker scout. Hell, I'd even buy it another time if they did an EU Rebel speederbike/scout too.