So....since she is actively trying to decorate her room, and not just being lazy and not picking up her stuff, should I let it stay?
My DD4 is exactly this way. She has to drape her sparkly beads all over things, paint "beautiful rainbows" and hang them up, create a "princess closet" where all of her princesses have their own beautiful things. She absolutely cannot go for a walk without gathering all sorts of flotsam from flowers to rocks to sticks to leaves that are all "so beautiful". She will present me a leaf, saying "Mommy, I got this for you!" and if you discard it too quickly (i.e. before she has moved on to something else) she will be devastated.
I don't try to make her put those things away, because, as you said, it's not left out from laziness or a lack of organization; if you ask her, it is completely organized and everything is exactly where it needs to be. I agree that you need to be able to move around, but I don't think that my DD organization should have to exactly coincide with mine. Plus, she's only 4, after all.
I would compromise -- make sure she is cleaning up the other parts of her room (toys/games/puzzles/clothes), but let her define how she wants to decorate. Perhaps it would be a good idea to practice at cleaning everything up; every so often we will put away all of her beautiful things by doing "clean up clean up" time together, but she knows she can redecorate after everything is put away.
I love the way she is always making something beautiful (at least to her!) out of something completely random. I want to make sure I go out of my way to encourage that creativity, which, as you said with your family, my DS5 does not really share.
