I really like the entire direction of the expasion! Although if i had to pick one thing... honestly for me, its mostly the removal of the auction house (even though this is old news). The implications of a global loot ratio made it so that when playing through the game you never were able to get any good loot, because it was all available on the scope of the ENTIRE player base, so your individual experience suffered, and you were almost forced to use the AH, which is not what i wanted to do... I just wanted to stomp some baddies with my friends. Hopefully this will allow them to better tune the loot ratios for individuals!
The new bosses are definitely the most exciting, Diablo has always been defined by its grotesque, monstrous bosses and it looks like RoS will only be raising the bar when it comes to the big bad bosses.
I'm really looking forward to finding out whats next for world of warcraft and also the next D3 expac. I enjoy both games and continue to play them. Really looking forward to reaper of souls and can't wait to play it with my friends so i cannot wait to see what else they have to show about the game. If i do win tickets i cant wait to see how my first time at blizzcon will be like and see all the things there for sure!