I think that the fights could be longer. The fights in dbz manga weren't that long, but the anime increased them. So, instead of pointless fillers, they should increase the fights. I would really like that.
Also, better animation.
As for the manga, I agree that some flashbacks are unecessary(madara and hashi throwing rocks, really?), but some are really necessary. Another thing is that kishi should kill some chars. I dont think that is extremely necessary, but some need to die, like gai.
At last, less tnj. I understand it's importance to the plot, but put the chars to constantly talk in the middlw of the fight, that becomes annoying. I think he should balance better the talking and the fighting.