I'm not onboard with the plan of dropping the bloke who clearly looked to be a level above everyone else today.
Also for all the praise Williamson gets, he is not brilliant versus spin in the middle overs. Where I feel he might be good is staying in there like Kohli keeping the run rate ticking and then finishing the game off versus pacers. In all honesty, unless Saha returns to his form of last season, they need both Bairstow and Williamson in the XI.
Pandey as a finisher would also not work. Even for India, every innings I watched of him was not like the one from a modern finisher, but more of a classical finisher like Bevan.