Whoa I'm very into the hand drawn look of the water effects in that OP. It's so rare to not have it look 3D these days. I was already into the super clean character designs and I planned on watching it eventually, but I may have to check this out now. It's getting some good buzz.
This is Jojo. Araki is always making it up as he goes along. I mean Golden Wind does have more of a plot in that from the beginning it's plot is just "find out who the boss is" but it's just as slow in terms of moving the plot along.
I think I'm gonna pick up Sarazanmai too. The PV popped up in my YouTube recs last night and from the thumbnail I thought it was some kind of magical boy show and it is, but they turn into kappas.