I left OP after MF etc. Same reason- far too slow pacing and it was when I was young. Today I could watch OP only for $$$.
I also hope they shorten the OP a bit, because this manga is truly brilliant and Oda has been working on this title for DECADES. With the new version, there will be no problem with fillers, they will take, say, an additional half a year break and by the time they reach the Vegapunka island, we will be 43-45 years old, if not more (if you are from a similar age as me xd).
I am already 45+:) Started watching exactly in autumn 2008, puff now 15 years have passed and the show is still going on.