I see, that's a shame. Not surprised about Jotaro, though, he is practically the mascot of the entire series, despite having as much personality as a wooden doll.It's not so much the idea is bad, but more the execution. Without spoiling it, you travel through a bunch of worlds gathering the Jojo's, then you have to travel back through them again for a stupid reason before having to beat the disappointing final boss.
TL;DR, it wanted to be Dissidia, but failed mainly due to repetition, everyone who isn't Jotaro getting very little screentime and the bosses not being very fun.