I've been following this for a while. The major problem is Cyanide have had almost zero contact with the community during the development and that any information regarding rule changes on the game is almost unavailable, the old school fans seem to be pretty up in arms about any changes to the rules outside ones that have been set by the LRB (Living rule book) as Cyanide was given artistic licence to amend the rules to the game as they see fit instead of using the time honoured and working rules already in play.
There are still a handful of bugs in the game from what I can see and some are quite game breaking for online play. They are supposed to be fixed soon though and I remember reading they are having an open question day on reddit next week possibly to solve the major issues they are having with communication, albeit a bit late since it is already released.
As far as I am aware it has a much more improved "campaign mode" which acts as a tutorial for newcomers but is still no match for the extensive revision and studying that is necessary to perform adequately in online play, so the learning curve is still very steep outside of beating the poor AI.
The final nail in the coffin for the game is the way they have been released, Blood bowl original had 8? races in the game to choose from they released a legendary edition that increased that to 20 and then final another full price chaos edition 2 years later putting it up to 23 different races in the game. They have gone back to 8 races on release again and probably intend to milk all it's worth with DLC.
I didn't pre-order, nor have I picked up the game yet and will be waiting to see if it is worthwhile in future, personally I don't think I will pay anymore than £10-15 for the game.
If you really want to find out if the game is for you or not I would recommend (if you haven't already) picking up a cheap edition of Blood bowl Chaos edition and see if you enjoy the gameplay and rules (it's a game of chance completely based on dice rolls) as they will be almost identical, it's only the graphics that will have changed a lot.