Because all Gattis needs to do is add a bit more spacing, not demand a "look-at-me" before every snap, and allow TVD and his WRs to work on their timing, and you would see immediate improvement (assuming no further drops).
All of those things allow TVD to get closer to his comfortable rhythm, while still retaining the basics of the personnel decisions, the playcalls, the blocking schemes, and the execution (notice, I left out "formations", which I believe are too tight sometimes when we line up, and went into the short side of the field too many times against aTm).