The best thing Four Doctors has going for it is a complicated time travel puzzle. Unfortunately that is about all it has going for it.
I loved the premise of the continuity bomb, a weapon left over from the Time War capable of rolling back an individual's timeline to a moment when they made a decision that could have led to the worst possible outcome and then reverses the decision so that the bad choice becomes reality. The bad version of the Doctor created by the changed timeline sets in motion a chain of events that will guarantee his timeline becomes real. A promising premise but in execution it gets very confusing.
It seemed like the multi Doctor aspect of the story was kind of wasted as 10 and 11 contributed very little. It might have worked much better as just a 12th Doctor story focused on the Doctor's self loathing that led to his isolation and decision to lash out against himself in the past.
Much more could have been done with the continuity bomb. I would love to see a series of stories where each version of the Doctor is forced to deal with a world where he made the wrong decision. Maybe the 1st Doctor decides not to steal a TARDIS and therefore all the good done by the Doctor is undone. Maybe the 4th Doctor does wipe out the Daleks at the moment of their creation but without the Daleks to fight the Time Lords become cosmic tyrants. Maybe the 8th Doctor chooses not to regenerate and join the Time War resulting in a Dalek victory. So many potential stories.