You cannot have a game that is about finding and upgrading items for your character that has drop rates affected by an AH. It stifles the will to go out and farm and the excitement you might have that you will actually find good items through your own work. When building your character is essentially outsourced to other people, the sense of striking gold when finding something great is diminished far too much to be enjoyable for me personally. I put over a thousand hours into Diablo 2, and 120 into three. I honestly think the people criticizing the AH are not some loud minority. The dislike of the AH has been too consistent and widespread imo for it to be that. It presented a genuine design problem that limited the ability to be self sufficient because Blizzard couldn't have drop rates near what they were for Diablo 2 since that meant absolutely FLOODING the AH with good items.
They wanted gold to be valuable and wanted the RMAH to stifle the secondary market, but is it worth it when you undermine one of the most fundamentally important aspects of Diablo in the process? If you can't get excited about finding items and upgrading your character, what is there? The combat gets repetitive after the first couple playthroughs of the game, and the items themselves weren't interesting in the first place. The items never had stats that gave you pause and thought "how can I break the game or reinvent this class with this crazy item I just found?" I think this is a good step for Blizzard simply because they need to worry about making the game more freewheeling in terms of items and abilities, not tightly controlled and balanced.
The AH for me hurt the game much more than it ever helped it, I don't want convenience when that convenience asked you to take away one of the pillars of Diablo. Finding your own great items that made you actually excited to play the game in the first place is critical for me. The sense of "I could find something incredible in the next five minutes so I'll want to play for the next two hours" was gone because of how drops and items worked. To be honest, I had two deal breakers with the RoS expansion. The AH and weapon damage being tied to skill damage (simplifies the equation to finding a good weapon far too much to be an even somewhat interesting choice). If the new weapons have some really crazy, BUILD CHANGING abilities attached to them I may reconsider that though, so we'll see. I really hope the new team and lead dev keep going in this direction, because it looks to be promising. To all the people that loved the AH, I'm sorry you won't be able to use it anymore (honestly, having a feature you love get taken out sucks). I too enjoyed the conveniences it gave me, but I was personally always willing to trade it away for revamped drop rates and items.