What I've been reading is while campaign mode and the lazy story mode are part of the problems, the major point people are making fun of (and angry) are how bad the balance of the combo system is.
The patch took out a lot of the infinites by making characters fall down faster, affecting all other working combos prior as well.
There was even a character (Wamuu) who's Super will not follow through on an enemy because the enemy falls down too fast.
A Blazblue developer had even complained about how someone shouldn't attempt to balance a fighting game overnight. (Never specifying who lol.)
Basically the bad word of mouth is due to all these videos showing how bad the fighting system is as til now, allowing everyone to mock at it.
Wamuu video : https://www.youtube.com/watch?v=MgSj0DXBXE8 (Videos shows characters able to counter despite being hit by a Super)
And here it is; I can get past bad campaigns in a game that touts itself to be a fighting game. But the sheer amount of stupid infinites on day one was kinda worrying (and not even in a Hotuko no Ken kind of way where everyone is broken but the core mechanics of the game are still fun in a silly way). But it's been awhile since I've seen a fighting game where characters can hitconfirm into a super and still be absolutely unsafe. And this is in combination with the massive amount of health that characters have that make matches really long? Man, this is straight a hot-mess.