On the subject of OT location sets:
Lego has released everything for Hoth, Endor and the Death Star, and with the upcoming Yoda's Hut, Dagobah is pretty much done as well. The figures for all those locations are pretty much done as well, with the exception of Force Ghosts and specific Imperial Officers.
That leaves Tatooine, Bespin and Yavin IV as the locations they'll focus on in future.
Yavin could be done with a large Rebel Base, around the £120 price, with four levels - hangar, briefing room, celebration room, control room. Figures could be the medal versions of Luke, Han and Leia, or pilot, normal jacket and white robe respectively. Add in Dodonna, Red Leader and his Droid and Rebel Technician and Honour Guard with a transport speeder and everything major is covered.
Tatooine from Ep VI is as good as done with the recent sail barge, skiff and palace, with only some of Jabba's gang to add.
Tatooine from Ep IV however has a few holes in it. The patrons of the cantina are an obvious one, but the Lars Homestead is a bigger one. I'd suggest the main above ground structure, as well as the below ground kitchen and garage being represented, along with a V-35 speeder. Luke, Owen, Beru, R2 and 3PO should be present along with maybe a treadwell or group. I'd also like to add in a tusken and bantha, making it similar to the precious cantina set in size and contents.
Bespin is hardest to suggest what is best as there is so much to include. Landing platform, apartment, dining room, corridor, 3PO's accident room, scrap room, as well as several locations where Luke and Vader duel. This doesn't include the carbon freezing chamber as we got one recently, but if these were all combined in one UCS set, you'd expect a new version to be included. A Cloud Car would also be expected. Figures would be Luke in dark tan outfit, Han in blue jacket, Leia in Red robe/white jumpsuit, Chewie, R2, 3PO, Lando, Vader, Boba Fett, Lobot, Bespin Guards, Stormtroopers and maybe a Cloud Car pilot.
For OT ships we've done well recently with Rogue One updating the AT-ST and Y-Wing. The TIE is coming with Solo, but there are a few ships needing an upgrade IMO.
B-Wing. The last one was so disappointing, it would be nice to see it done right. For figs, a B-Wing Pilot, rebel officer of some kind and a technician.
TIE Bomber/Interceptor. These haven't even been made in grey rather than blue yet. Going with three figures for each, one pilot per kit, with Death Star Trooper, Imperial Crew, Motti and Tagged making up the others.
Slave One, once the UCS is gone. This may be a good place to give us a Zuckuss, with Boba and maybe a Bespin Guard. Han in Carbonite goes without saying.
The Imperial Landing Craft. It would be nice to see this remade, although I doubt it's anyone's priority. It'd be a good way to get more sandtroopers, maybe another Dewback.
Tantive IV. It would have to have the bridge as seen in RO at the front, a corridor through the centre and the escape pod area at the back. Leia, Vader, R2 and Antilles are must haves, maybe two/three of a rebel trooper, stormtrooper, 3PO, a black suited imperial officer (jir or praji) or the striped R4 unit (R4-M9).
Super Star Destroyer. This should be constructed in a similar style to the FO and Imperial Star Destroyers, but slightly longer. Inside should be the bridge and Vader's chamber, a projected emperors if there is room. Vader, Piett, Ozzel, Imperial Fleet Trooper and two Imperial Crew should be the figures.
Home One. The interior should be similar to the last Home One set with the bridge and briefing room connected. A hangar with ships similar to the mini TIEs in that Rebels set would also be good if there was space. Ackbar, Mon Mothma, Madine, Nien Nunb, rebel technician and a Dressellian would be a great fig line up.
Nebulon B and a GR-75 would be great, but have next to no play value.
I think that about covers what we need, but a few battle pack ideas too.
Rebel Pilots battle pack - three pilots (Tiree, Pops Krail and John D. Branon) with a technician.
Death Star battle pack - two Death Star troopers, stormtrooper, imperial officer (grey suit).
Imperial Crew battle pack - two imperial crew, Death Star gunner, imperial officer (black suit).
Hotham battle pack - two hoth troopers, two snowtroopers.
Bespin battle pack - two Bespin Guards, imperial officer, stormtroopers.