If we take a break from the shockwave and swordsmanship and swordsman copium, there are other points to also discuss
The first and foremost as per new leaks is that the Admiral was killed by Rocks before the clash with Harald and Rocks later thinking that he can beat WG with Haralds help. The obvious implication is that the Admiral was not more than a mid diff (high diff at the very best) fight for Rocks and that Harald is PK level, right up there with Roger and WB.
The Admirals can no longer be treated as being at the level of the Yonkos when you have Roger/WB/Shanks equal Rocks mid diffing one of them. It now makes sense why Oda has shown Old Garp stronger than Aokiji and why 20 year retiree Ray could stall an Admiral in prime.
Rocks swordsmanship is the real deal by being able to destroy the gates of justice, seems like this feat is getting underrated. WG and Imu are going down this arc.