The angry customers and the state of the game are problems.

• it's hard to feel sorry for people who pre-ordered because they got exactly what they paid for - a game of unknown quality and quantity of content
• it's hard to feel sorry for people who bought post-release because they also got exactly what they paid for - a game where reviews detailed poor quality and quantity of content
• customers being disappointed and/or wanting a refund is perfectly reasonable
• people wanting the game to be better is also reasonable
• people abusing the devs is not reasonable

I'm not going to defend the poor quality of the game because it's obviously bad (from what I gather, anyway - I've not played it myself) and should be improved. But I do think gamers could learn to be a little more responsible with their purchases and inform themselves before buying a game.

I'm pretty over the whole cycle of games coming out and not meeting expectations, people buying them anyway (through pre-orders or day-one purchases), people being unnecessarily rude/hostile/sending death threats to developers as if they were forced to buy the game as gunpoint. Yes, developers should try to do better, yes publishers should often give developers more time to polish up games rather than announcing the release date two years in advance and refusing to delay, but also consumers could really take some responsibility for what they decide to give money to.