Yeah, but Josuke's hair is WAY better.

Let me add some more similarities:

- both their missing parents have an alter ego (Tequila Joseph and Rose Quartz), like to use the "run away" tactic (and both Steven and Josuke, coincidentally, don't);
- both Josuke and Steven's grandparents (great-uncle and great-aunt in Steven's case) were pilots;
- both boys can fuse people with rocks (Steven himself with Gems and Connie, and Josuke fused Angelo with a real rock);
- both revived their friends, who got special abilities thanks to that (Lars and Koichi, although, it's a bit of a stretch, 'cause Koichi didn't die).

Also, Part 8 Josuke is a fusion (sorta) between two people, therefore any fusion is a Jojo reference.