Believe me, Tsunade and Sakura are my favourite characters in Naruto, but your statements are a little out of proportion.
Sakura is a talented medical ninja, but Shizune is better, and that's why Shizune is the general of the medical corps, and not Sakura. Yes, she did beat Sasori, but not only did she have Chiyo on her side, Sasori allowed himself to be killed, and I believe he never went all out. Although she did fool Zetsu and managed to find out how he works, the former has been accomplished by fodder ninja, while the latter is a good achievement. Lastly, Sakura healing people such as Kankuro could have been done by most medical ninja.
With Tsunade, I do agree that she is overlooked. Maybe not top 10 material, but people don't realise how well she can fight. Being the only member of the Senju clan remaining isn't a feat, it just means that she has outlived her ancestors - no skill involved there. I wouldn't say she is the 2nd strongest Hokage either, but rather the weakest - but that DOES NOT mean she is weak at all. In fact, compared to a lot of people, she is still incredibly strong. She's also not the strongest Sannin. Jiraiya was offered the position of Hokage before Tsunade, and Orochimaru was the first choice before J-man, but he had became a villain by that point, so of course he wouldn't be offered Hokage. A total of 35 in the databook is impressive, but we all know those numbers do not equal their abilities in battle. After all, I'm sure others will have higher scores. Lastly, she is of course the best medical ninja to ever live.
Overall: Tsunade is overlooked & underrated, as is Sakura, but you are overrating the latter quite a lot.