I am absolutely addicted to Rock Band Blitz; I believe it is an utterly amazing game, and the way it works with existing DLC is pure brilliance. As a longtime Rock Band player with over 1300 songs in my library, I feel like this game is a virtually endless goldmine that combines the musical interactivity of conventional Rock Band games with the addictive qualities of a brainy puzzler like Tetris.
I am, however, extremely disappointed that Harmonix has effectively rendered the ability to play the game completely dependent on your Internet connection, the XBL/PSN service, and the Rock Central servers, none of which will ever be particularly reliable for many people.
There is nothing more frustrating than being in the middle of a great run on a song, only to see that the PSN has randomly booted me for no reason and knowing that the entire run is completely for naught because there is absolutely no local score saving. The only thing you can do when the Internet is down, or one of the online services kicks you, or if the Rock Central servers hit a snag, is essentially play Practice Mode WITHOUT powerups.
Especially for a solo game, this is extremely disappointing and frustrating. There is absolutely no reason why you shouldn't be able to play the game exactly as you would if you were connected with the exception of posting scores to the leaderboards. I've suffered from the PS3 Rock Band 3 crash, but at least with that game I can still play the game and track my own high scores. Rock Band Blitz is utterly useless if any one of the three mentioned variables hit a snag, and it really sucks to constantly play the game with the fear that at any moment the bottom could fall out and I not only lose my performance on the song I'm playing, but I'm also left with a skeleton of a game until something outside my direct control is resolved.
I understand there are some benefits on the developer side (i.e. tweaking the coin economy without patches, as we've seen) but it's a nightmare on the consumer side and I really don't see how difficult it would be to store local copies of the relevant variables and then sync them back up to the server when a connection is restored. The only unavoidable drawback to losing a connection should be instant leaderboard placement.