Oooh, ok. I was about to ask another series of questions, but I think I understand what you mean. It's sort of like making a new tool, or building blocks that can help build your project, but like any tool, you have to test it to make sure it works properly, otherwise, it may lead to unforseen issues down the line. And depending on how complicated that tool is to use, is a big factor in how long that peice will take to complete. Am I close?
True, no world shown as of yet has really been out of left field. Well, I guess technically Monstropolis was sort of out of left feild, but it was spoiled *months* before it's reveal (which is when most people were shocked). Princess and the Frog, as a world, though very possible, I don't necessarily think is likely. Hmmm... if Tiana does appear, it might be in a similar fashion as the PoH from KH1, where they only appear under unnatural/endgame circumstances.
P.S. Congratulations on finishing your Squirtle! ^^