IMO as Hokage she should have joined the action to fight against pain to keep the losses to a minimum. But instead she relied on someone else, as Hokage that shouldn't be allowed IMO. Yes she is powerfull that's why she should have fought IMO. I mean sure she should trust Naruto but really thinking about leaving all 6 pains to Naruto, while Jiraya, who was before the training many times stronger then him couldn't beat him, is IMO stupid of both Kishi's plot and Tsunade.
Also yes I do think her healing abilities are incredible and all. Also the most epic moment of her in that arc was when she went against the orders of the elders. But I think the only moment that she showed her real battle strength was against Orochimaru who was unable to use any real jutsus except for using his snake head and the blade that came out of his throat. Also the fight against Kabuto was good, Though I still think that the power diffrence between Kabuto and Tsunade was to small in that fight, I mean before blood was shown and all.
But I don't really care about that since the Naruto Vs pain arc/fight was epic
Also I do like Tsunade but I just expected more from her being 1 of the Legendary sannin.