Majority of people claim that Kizaru is no match for Luffy, or that he is the weakest original Admiral, or that he doesn’t have strong enough Haki etc.. The most ridiculous claim lately has been that he is just on par strength-wise with Seraphims.
Facts we know about Kizaru:
-Advanced Armament Haki (shown against Whitebeard, used it together with Akainu and Aokiji).
-Advanced Observation Haki (forming his body to avoid Haki-based attacks from Whitebeard, similarly as Katakuri did against Luffy. Akainu and Aokiji both did this as well in Marineford).
-Top tier attack power (implied by Marines and Vegapunk, as they chose his laser to be utilized with Pacifistas because of its strength).
-Never scared or worried so far.
-Inflicted heavy damage to Whitebeard without taking a hit, almost toying with Whitebeard as he teleported on the top of his weapon and spammed Whitebeard with lasers.
-Did not get hurt at all in the whole Marineford battle, unlike his fellow Admirals.
-Clashed evenly with Rayleigh.
-Would have gone to Wano to “settle things” after hearing that Kaido and Big Mom formed an alliance.
-Non canon: In film Z he was referred as a “monster” back when he joined the Marines as a rookie, alongside Akainu. Take it as you want, but for me it seems that they were considered as equally terrifying and strong.
I’m not fan of power level talk at all, so I also find it dumb when people try to classify all Admirals as “Admiral Level” and think how they’d fare against “Yonko Commander Level” or “Yonko Level”. We don’t know for a fact how these fights would turn out. It has also been stated multiple times that match-ups can go any way and it’s more about individuals rather than these fan described sub-classes.
The FACT is that Admirals are Navy’s strongest military might, the trump cards, the pinnacle of strength. They are always a threat to the pirates they choose to go after.