Not true. This the second arc in a row without the matched opponents. The fishman island only gave Luffy a decent sparring partner, and even that was so-so because the opponent was such a bonehead (or is it cartilagehead since he was a sharkman). Of course before the time skip the Shabondy arc also hardly had such a clean setting either.
In fact I gladly prefer that one episode where Zoro finally stood up, saved Tashigi, and overpowered Monet over any generic fight. It was so bloody badass.
Just because you didn't find them threatening doesn't mean Oda still didn't create a unique opponent for each of the Strawhats in that arc. They had names, personalities, unique abilities and they each went up against a specific member of the crew.
Contrast to this arc, where there were really only 3 villains, and one of them faced off against characters not even on the crew.