It seemed as soon as Ashi figured out she had full control over Aku's powers she almost instantly sent herself and Jack back into the past without an ounce of hesitation. There wasn't a moment where her and Jack discussed the matter, perhaps after a future Aku defeat. If there was a few more episodes in this season there could have been possibly two Aku death scenes (One during the future and one after going to the past) or something to that example. There could have been scenes of some dramatic discussions of whether or not Jack would want to return to the past if he thought it could result in the disapperence of Ashi. I suspect the ending may have been the same in the end, with Jack/Ashi choosing to destroy Aku back at the beginning to undo all the death and pain. However if this season was a bit more fleshed out giving us more time with these characters we have grown so attached to, it certainly would have be the icing on the cake.
I know more episodes with the Scotsman would have been lovely
This is not to say I didn't highly enjoy this season, in fact I was enjoying it so much I would have loved to have more of it