Well he did have Kizaru say something, he basically said he can see how Luffy took down Kaidou.
If you want the rest of the series to go with opponents commenting on Luffy's haki specifically, you're in for disappointment. Powerups from previous arcs often become routine moving forward, we're dealing with top tiers now.
There is no better praise than acknowledging Luffy is capable of defeating a near 5 bill Bounty Yonkou in Kaidou. It means Kizaru has acknowledged Luffy as a top tier, and chapter 1000 Luffy is no top tier.