WRONG! we do not know anything about Danzo.. except that he was a big coward and was hiding all the time. Most likely bodyguards of Danzou were even stronger than him(together). Since Sasuke was learning from Orochimaru who was a "jutsu gatherer" there are endless possibilities how Sasuke could avoid getting killed or beaten down if he was alone or in a sticky situation with 5 kages and so on. Since most of them underestimate him because of he Uchiha drama they don't know what he is capable of especially if you haven't noticed Sasuke's strenght is that after each fight he gets lots stronger.You say, "If you know you have a healer at hand, you can use strategy involving healing afterwards. If you don't have a healer, you must do things so you don't need one." But the fact is there IS nothing he could do to fight so he wouldn't need a healer. Because he's WEAKER than these people he's defeating. If he didn't have his healer, he'd be LOSING these fights, no matter what he did.
Sure he could prolong the fight with smart tactics and find the enemies weakness with longer time, but as some people are agressive poker players and some passive, he clearly is agressive and in his case with susano & all the other stuff he has under his cattle he obviously has everything to be agressive & reckless.