You objected to the use of the MMO term. While no-one is saying that this is the new definition of what it is to be a MMO, they are saying that it is not as far off as what your post seemed to suggest. The auction house alone makes it very similar to MMO's that use instanced quest areas, like Guild Wars and Dragon Nest.
Would it only count as an MMO if you had the ability to see everyone's avatar at the same time? Is a huge sin to call it as such to compare the changes in D3 that separate it from the games currently in the same sub-genre?
You have built up yourself as a brains trust of different sub-genre's but you seem rigid in how things fit together. What will you do if the Diablo universe starts adding instanced Auction houses that 'everybody' can move around in at the same time, or any other number of little things that will make it slowly more like recognized MMO's and less the action rpg game that it is. Will it need a new genre for you to accept discussion about it while the rest of the community are happy to just say that it shares features with MMO's.
The more complex the programs of an organism, the greater is the danger of insanity. It is very, very hard to be a god.