Yeah, it's pretty insane. Famitsu got caught with their pants down on this one, hard. The reviews from Japanese gamers have been some of the worst I've seen for any major release.
Oh man, I forgot that Famitsu gave the game a 40/40. That's just...

.
I haven't played it, but reading user reviews, everyone thinks it looks and sounds great, but .... apparently the online is totally broken, the loadtimes are shit even with a large required install, it's eating saved games, it's missing a lot of the popular characters (carved out and sold as day one DLC, apparently, 600 yen a pop), the balance is completely broken, the story mode is apparently done super cheaply with few stages and a lot of the story being told just by text, the AI is super cheap... lots of reviews basically saying that apart from the graphics, sound, and originality, there are too many problems to list.
You're pretty much right on the mark with everything you said. I can't comment on the online as I have yet to try it, but it feels like they did an amazing job with the visuals and match presentation (the super moves are awesome), and everything else kind of sucks.
The Capcom JoJo's fighter HD re-release on PSN/XBLA still shits all over this game from a gameplay standpoint.
yes, well, fun is apparently an issue here. in that it's not. at all.
I've had some fun with it in the time I've spent messing around. It's just nowhere near being a "40/40" game. That score is ridiculous. Even with all the complaints, people still seem to like it or combo videos wouldn't be popping up on streaming video sites.
why the heck you would do an all-star fighting game and carve out so many favourite characters for DLC is beyond me. imagine if you bought marvel and you had to buy spider-man, captain america, iron man, hulk, ryu, dante, chris, and viewtiful joe each separately for six bucks a pop.
What missing favorite characters are they talking about? All of the main characters are in. The DLC characters are all minor characters- it's not like you're describing at all.