I doubt it will ever happen. First of all, there is no Battlenet for consoles; the online is managed by Sony and Microsoft.
Second, console and pc don't play the same; not only on desktop there isn't a dodge button (that we don't need) but the pace of the fight is too different between the platforms.
Third, even with the AH removal, i doubt we will see the same loot system. Console version is completly self-found, even too much, where you can swim in legendaries with inflated stats. PC will mantain a bit of trading with the shutdown of the AH (at least, i hope, i don't want to be full BiS in a week of farming, i want a carrot on the stick).
Even if these two versions share the same name, there are some barriers that aren't possible to pass.
Now, thinking about it, it isn't possible to play, for example, Borderlands 2 on PC with players on PS3. Yep, cross platform is just a dream.