I don't think I'd go as far as saying that. He's not the clearcut best RP in baseball anymore, maybe/likely not even top 3, but he's definitely a relief ace IMO.
Altuve beat Kipnis last year in:
-HR, by 6
-RBI, by 12
-Avridge, by .010
-SLG, by .008
-And uh, SB by 26
Altuve also projects substantially better, and is 25 to Kipnis' 28.