You can also bazaar them and then remove them. Not the flashiest way to sort things but it works, so whatever.
And they already have an auto sort feature, so they don't need to add another one, they just need to tweak the one we have so it can combine partial stacks, which they probably will eventually... They have a busy schedule of things to do though, give them some time for minor things like that.
It would be nice to get a regular sort(like the auto sort except one time effect and not toggled) and manual sort feature though, so you can have the stuff in your inventory sorted, but still let new stuff appear at the bottom of the list. I find myself toggling the sort on and off all the time, and would prefer a non auto sort. :P