Had they concentrated on palpatine, anakin would have been left adrift. He had only just made his choice. He was no longer a jedi, but he had no idea on how to be a sith. He wouldnt have even known where to BEGIN finding sith techniques, let alone the one he went evil for, a way to save padme. Im seeing a blind rage berserker anakin going around trying to kill everyone he blames for costing padme her life. (if she died) Im also picturing him dying quickly, as he is jedi trained, and blind rage doesnt work too well for them. As a fully trained sith he would know how to use it, but he isnt a trained sith, so it would make him weak and easily killed.

Or he would be sort of another Aurra Sing. A bounty hunter with jedi training. Constantly being hunted by the jedi order for his massacre of the younglings, and hunted by the entire republic for the same reasons. But I tend to think he would only go that route if he survived his blind rage reaction to learning that palpatine is dead.