Looking at them isolated, Wano is a much better arc.
But Wano is NOT an isolated arc. Wano is the culmination of every arc since Punk Hazard (with a lot of elements from FI).
Wano/Onigashima are the "Infinity War/Endgame" of the Post-TS.
And they suck ass as being a "conclusion" for this massive storyline.
So the level of "disappointment" of Wano makes it a considerably worse arc than FI, which was...just a "presentation arc" for the SH's post-TS.