I think you were referring to Rebel Troopers and not Clones, and I agree, the necessity of a headsculpt and a lot more complicated tailoring involved for something like the Hoth Trooper or Endor Commando means it's not likely Hot Toys will attempt them.
Along with not requiring headsculpts and using a lot of plastic parts, they also seem to intentionally keep troopers priced lower with the assumption that a fair number of people will buy at least two. It would be harder to sell Rebel Troopers as army builders without requiring at least a few different diverse head sculpts.
And they know armored troopers are popular enough with broad market appeal to make producing a large quantity a safe bet. They may not want to take the risk of producing something like most Rebel Troopers, which are just humanoids in clothes with a helmet.
The only one I could see happening realistically would be the Hoth Trooper since that could technically be done without a full sculpt with goggles and scarves and face wraps. But that's still unlikely.
I would be okay if Hot Toys or Sideshow wanted to offer something like a Star Wars uniform pack which people can put on any 1/6 figure of their choosing. Rebel Fleet Trooper, Hoth Trooper, Endor Commander, various officers. Even Imperials like the Death Star Trooper or AT-ST Driver.
