Here's some food for thought:
a) Maybe some of the smaller game changers have been asked and have turned it down.
b) The lots can ONLY be built with the base game and the new pack. No moo, no alt placement, no sizing up/down, no debug/live edits items, no cheats allowed whatsoever, and most importantly, a very limited amount of things can be used in a build to allow for low end computers. You're not even allowed to use more than 2 or 3 different wallpapers in your build. Therefore, the builds are going to be a little on the bland side no matter what.
c) Many of the builders out there that you guys are mentioning (like Marmalad or Simpiration) don't do builds that don't involve using MOO, or using the Tool Mod, or using cheats like debug/live edit. So would they even want to build a very basic, limited, boring build for an official expansion pack? Or maybe they've been asked and turned it down for that reason?
d) Each build made gets submitted to the devs 2-3 times before it gets any final 'okay' to get added into the world. They go over each build with a fine tooth comb and list the things they want removed or changed by the game changer. Therefore, it might actually be the devs who are nixxing fun ideas out of the builds. There are loading time requirements, game performance requirements, etc that all need to be taken into account.
e) You see many of these game changers going back to their expansion pack builds and re-building them in a new youtube video for that reason... they weren't allowed to do the things they wanted to originally.
f) It takes a very brave person to build something that will be permanently in the game with your name permanently engraved on it. Not everyone is brave enough to put themselves in such a vulnerable situation that could open the floodgates for some very ugly criticisms and personal attacks on twitter.
