Well technically any Hokage is a better Hokage than Danzou considering that Danzou was never Hokage in the first place... He was just Hokage Candidate, that had good chances of becoming Hokage, and a fill-in for Tsunade since she was out of commission atm...
OT: But yeah... In terms of fighting, Danzou could crush Tsunade high dif
In terms of leadership, His decisions may seem harsh, but they get the job done in the end.
In terms of the backing of his subordinates, Not a single one likes him, and Tsunade is loved by most Konoha shinobi.
Overall, I would say Danzo could be a better Hokage than Tsunade, IF he lived to officially get the title...