Im not in total disagreement here but what your not acknowledging is that Sakura was on par with Tsunade on a technical basis after only three years of training and at the age of 17. That in itself alludes to Sakura's potential being above Kage Tsunade since she actually excectued all of Tsunades prominent jutsus, the Strength Of A Hundrered Technique being an example. Madara acknowledged Tsunades Regeneative Jutsu as something resemblant to Hashi's abilities, Tsunades reveal of that Jutsu was in fact her standout moment during her battle with Madara. Chapters later Sakura used that same technique when she charged JJ Madara and he in fact acknowledged it as the same one Tsunade debuted before him. So it would be disingenuous to set here and say that Sakura fails in comparison to Tsunade and doesn't have the chance of surpassing her when they preformed equally in battle from a techniqal standpoint.
I would like to reiterate that Sakura only trained under Tsunade for 3 years and in only three years she became someone comparable to Tsunade, so imagine what she did with 15 years. I mean it's clean that she's gotten faster (she Blitzed Shin) and that she has a greater handle on her physical strength (she reduced a flying wall into small fragments of debris with one specific light strike).
