Blizzard was consistent with great game, until now. Diablo 3 is just a sad, disappointing, and dumb down.
Remember the skill tree, boosting the stats of your choice when you gain a level, all the gems? They are all gone. Stats are automatically assigned as well as skills with every new level. There are also only 4 gems now. In D2, you could make 3 different versions of the same class. In D3, the characters are virtually identical, so playing with other people with the same class is very dry now. In short, the game play is extremely simple.
I now discuss the challenge level of the game. Most the time, the game's difficulty is just right. There are a lot of elites in the game (special monsters with perks and are tougher to kill), most the time they are manageable, but once in awhile you will run into one that is difficult and end up kill you a couple times. The real problem with challenge comes with the Act bosses. They all share the same flaws. First they tend to have way too much health, so battles become endurance matches. This is especially true with Diablo himself, it took me as long as 10-15 minutes to beat him, he has just that much health. They all share area attacks that are hard to avoid at times and really do some damage. They all posses what I call a cheese attack that can kill you with one hit. Mix in the long battles, and you can easily die and waste a good 5 to 10 minutes in a snap. Very aggravating. In short, the difficulty is rather unbalanced.
Blizzard also put a steep curb on experienced gain for replayed areas. So if you crawl, walk, or run, you are going to end up as similar levels in the long run. This causes a problem if you run into an area that either is above your skill level, or is just difficult for you selected class. If you walk or run, getting to level 60 does not take as long as in previous games. Getting to level 60, is not a great accomplishment as it was in previous games.
The game is still a lot of fun, but it just doesn't have the magic or the deep game play that the other Diablo games had. Many of my friends have already walked away and are bored with the game. The graphics and sounds are great and do a lot to draw you in. Once you are drawn in, you are exposed to what seems to be a rushed game.
The biggest flaw with the game is the required access to battle.net. If battle.net is down, which happens more often than you might think, you aren't playing. This also lets a bigger threat than Diablo to attack, the Lag Monster. The Lag Monster is going to take big bites out of you and it will affect you for long periods of times, and often. Even on a Wednesday night, I was suffering from lag. I just can't complain enough about the problems with being connected to Battle.net all the time, it just drags the game down to a awful level.