@lucid
Thanks for the reply! I was not worried about the editor itself - really about in-game performance. But since it's a planned feature, and is already on some plugins, then my worries are gone :)
I must admit didn't read all the 13 pages of this thread... but there is 1 feature which would be essential in my opnion: to be able to use a single image as a source for "sprite parts".
Otherwise I may fear Spriter may actually cause a huge performance loss because of all the texture swapping going on on each character.
Is this a planned feature? I couldn't find anything anywhere about it - and in my opnion this is something essencial...