Databook is just an indication,both Jirayia and Oro have shown better feats in battles.
Tsunade wasn't alone against Madara,it was five kages fighting Madara,who was just toying them and he had no intention on taking them seriously.In any case,Naruto and Sasuke are on a higher level than Tsunade,so I really don't see Sakura keeping up with them.
That blooming thing doesn't have much logic to be honest.She was in life risking situations many times,so if she had something more to show,she had a chance.I just don't understand how she could advance in any level since she had zero training or there wasn't any indication that she was developing something.
Of course I don't expect her to be on the same level with Sasuke or Naruto (to be honest I laugh hysterically when I read that panel).I would be satisfied is she used her power to actually do something other than just standing,crying and talking.I do expect her to surpass Tsunade,only because Kakashi said she will not because we have any valid indication of that,but that statement of hers,that she is in an equal pairing with the other two??No, that was just wrong for so many reasons...