Even though she might have been blonde in the original comics, Teela will always be a redhead to me. I voted for the original bun, but hair up or down it doesn't matter to me as long as it's red.
A blonde Teela to me is like a universe full of Skeletors or even the Teela/Sorceress split. They're just very old ideas that didn't work out in the end.
We already have a heroic blonde in She-Ra anyway, let's have some variety.