While it's never bothered me too much now that you mention it, it would be a nice addition but one that I won't complain about if it doesn't get added. I have every skin for Ashe and honestly Project is nice but it gets a bit old. I mostly swap between Project, Championship, and default, sometimes Heartseeker or something too for thematic fun. But I'm also in the camo that since she isn't anywhere near slated for a VGU the last of her really old skins (Sherwood and Woad) should be removed in place of new ones since that's what they seem to be doing to her, vaulting Freljord and Queen for Project and Championship.
But I digress, the toggle would be nice but it isn't game breaking.