The skill tree in it is pretty epic.. just wish it was harder
I had that complaint too, and luckily some of my friends informed me that the initial play through is joke easy so you get a feel for the game. Apparently when you get past that though it is a hatefest of murderous monsters. I haven't gotten to that point yet but I am interested to see if my character build holds up in the harder difficulty.
I'm trying to relate to the common complaints I always hear;
"Great gear is too hard to get, I always get garbage"
"I have bad gear / started late, it's so hard to catch up to everyone else"
"This char is OP, that build is OP"
I have a feeling it might have more to do with expectations that have grown over 12 years.
I find it interesting the way people complain about Diablo 3. Looking at your points:
1. Great gear is harder to get in Diablo 3, but that's also because you could just chear in Diablo 2 and duping items was so easy it was comical. That's why the game has always online, so people can't just spawn characters in third party software and skip straight to being a murderous harbinger of death. You also have to consider that most gamers who played Diablo 2 at launch are no much older, and don't have as much time as they used to, so they consider any amount of time they spend as wasted unless they are constantly getting amazing loot.
2. It's easier than ever to get caught up since decent items are so cheap on the AH. With like 1m Gold I was able to replace 2/3 of my gear after 6 months of not playing and plow through Act 2 Inferno.
3. Unlike in Diablo 2? That's a laugh. Diablo 2 gave you more choices but there were certain specs that a lot of people used because they were comically powerful. I remember one of the Amazon and Sorcerer (can't remember what the exact class names were) specs were basically bread and butter and allowed you to kill everything on the map with ease. Diablo 3 doesn't have any specs like that which I know of.
Another common complaint is that the game is super repetative and you run the same stuff over and over--you know, because
nobody just chain ran Baal in D2, they continually went to different parts of the story to farm gear right? No. Diablo 2 was just as bad if not worse since it didn't have Monster Power and was very lazy about procedural content generation.