how does she not? (by feats)
By feats?!!!!!!!!!!!!!!!!!!! Here are the feats of these two. Let's see if they compare:
Minato:
Single handedly destroyed whole platoons during the third war. Earned the title of yellow flash. Destroyed Kanabi bridge along with Kakashi and Rin which apparently played a crucial part in the war.
Owned the Ay- Bee combo (or at least just Ay who was still the raikage after all)
Defeated Obito, saved the village from being destroyed by Kurama and sealed Kurama inside of Naruto.
Saved the shinobi alliance twice from juubi bijuudamas.
He was crucial in the fight against Obito, saving both Naruto and Sasuke multiple times. He was also crucial in linking up everyone so that they could help pull the bijuus out of Obito.
Removed Madara's gudoudamas in the fight between Guy and Madara (which would have hit and killed Guy by the way if Minato had not done that).
Now for Tsunade:
She beat up Orochimaru that one time.
She healed Naruto, Sasuke, Lee, the 5 kages, the shinobi alliance and the whole village on separate occasions.
She countered Chiyo's poisons and helped in the 2nd war along with her team mates.
Those were their successes. Now let's look at their fails:
Minato:
Failed to kill Bee during the 3rd war
Died to Kurama
Got owned by Rikudou Madara.
That is it (do not even bring up letting Obito almost die and letting Rin die because Minato had no control over that. Kakashi was a jounin, so he was in charge and he was responsible for his team. Don't bring up Kushina dying because he couldn't just let Obito blow up Naruto. By the time he got back, Kurama was already extracted from Kushina. Minato did not know at the time that resealing the beast inside of a jinchuuriki would save them. Remember, the plan to seal yin Kurama inside of Naruto was a plan that was communicated to Minato by the Kuramas after yang Kurama got extracted. This means that it was new information to Minato. Therefore, Kushina's death was not Minato's fail. Do not bring up Black Zetsu stealing yin Kurama because anybody can just be intercepted like that. Plus Black Zetsu is considerably crafty. Even Rikudou Madara got caught by Black Zetsu's deceptiveness and element of surprise.)
Tsunade:
Lost to Kabuto (part 1). Had to be saved by Naruto.
Lost to Pain/ Got put into a coma
Lost to Madara (pre-jinchuuriki)/ got chopped in half (in a 5 on 1 battle)
Now, numerically (in terms of the number of things I listed) they are almost equal (even then Minato is still ahead a little). However, consider the magnitudes of their feats and the magnitudes of the opponents that lost to.
Summation: Minato >>> Tsunade