(Sigh) As much as the dramatic part of me would love to leave you hanging there, the rest of me tells me to explain. (Especially since that might come off as rude.)
This has been suggested dozens of times before. Turned down by the devs every time. one of the biggest challenges in the game is SPACE! and this would reduce that feature. Additionally, your headline is completely misleading. Rotating buildings would not 'increase creativity' it would DECREASE it by making the game more convenient. Many of the upgrade changes are just a change in orientation, so rotating buildings would completely eliminate that.
And of course, it would be a crap ton of programming for a feature the developers don't even want. There are even more reasons, and if you want an even more thorough report, I suggest asking SoggyShorts.
EDIT: Hey hey! SoggyShorts posted just as I published!
@SoggyShorts, I tried looking for that Planks orientation change in ElvenArchitect, but I couldn't find it. They never change in just orientation, always in size...