Diablo 3 when it first came out was a fun game but not what the world was use to from Blizzard. There was 5 classes just like there was in D2. The game looked great and the poweres flashed and banged all over the place. What was missing was the randomness of the previous games that kept ppl playing and wondering what was next. The other thing that was missing was the ability to place points where you wanted to and make your own hybrid classes. Now this is also a new time and age of change in games. That is what the team was trying to do. Then they had the Auction House. It had its ups and downs.
Now tho, That has all been fixed. Act 5 keeps you playing and adds side quests here and there and they aren't easy either. They are tough. I played up till the Blood Marsh on Torment lvl 1 and at lvl 68 I had to turn down the difficulty to Master on my Wizard. The new gems that drop are a God send. The item loot drop 2.0 has made it a lot better to get loot and feel awesome for getting it yourself without the use of the AH.
I play a Wizard and Ill touch on just the one new spell they get. The Black Hole sucks you in and never lets go. I use the Frost affinity rune. So when there is a large number of mobs on my screen I plop down a Black Hole and sucks them in and it give me a boost to my Frost Damage spells for a while. The more you suck in the better.
The new Artisan Mystic allows you to transmog your gear with the graphics of previous items you have worn. Normal items are 500 gold while the legendary looks are 50,000 gold a item. Also she will enchant a weapon or armor for you.
Now I haven't unlocked Adventure mode yet but I heard it can turn a nerdy little boy into a giant LOOT WHORE! Loot and killing everywhere one you beat Act 5. These bosses are fun to fight and don't one second think they will be a cakewalk.
This expansion has given LIFE to Diablo 3 and I Think its just getting better. there is still talks of a pvp Battle Arena. Oh and the Paragon lvl system has the potential to make this game playable for a very long time !!