I'd move it around to add more time around Hiroshima and squeeze a trip to miyajima in there and Shukkeien gardens.
I spent 3days in the Hiroshima region and it wasn't nearly enough I would easily have given up one day of Tokyo, mainly because you can do about 3parts of Tokyo in one day due to the fact most places of interest are only a few minutes on a train away, but things near Hiroshima are more than just1-2stops away.
Anything particully you are going to Sendai for? It is a long train journey there and back, same thing for Fukuoka really, you don't want to spend all your time on trains
If i remember right i didn't go to Fukuoka at all because of how long and how many trains it would take.
I guess your flights are too late to change but when I go I fly into one airport (osaka) and out of another (tokyo) so I don't have to double back on myself when travelling about.