Proving Grounds as a Requirement for Random Matchmaking

Blizzard has announced a new prerequisite for queueing in the dungeon finder for heroic dungeons. In order to be put in a group (NOTE: This ONLY applies to randomly-assigned matchmaking groups. Premade groups don't have to worry about this,) you must first beat the silver-level Proving Grounds challenge for your given role.

So, if I want to tank Heroic Auchindoun (random example, it's the only Warlords dungeon I could name off the top of my head,) I first have to get through the silver-level tank challenge.

Two big things here have not been confirmed:

We don't know if success in the Mists of Pandaria challenges will count toward this. I have silver in DPS and Tanking, so I'm mostly set. However, there will be an updated version of proving grounds, so these may not carry over. No word yet.

We also don't know if this will be per-character or per-account. Currently the Proving Grounds achievements are account-wide, but while there has been no such announcement, it stands to reason they might require you to do it on each class or character on whom you plan to run.

A couple other notes:

Given that this will no be a requirement, Blizzard says that they will try much harder to make sure that Proving Grounds is balanced between classes and specs.

Quest gear should get you into level 100 normal dungeons and scenarios, and the gear from that is should get you into heroic dungeons (not that this is news. This has been the case pretty much since heroic dungeons first existed.)

This will not be a requirement for LFR, and in fact, gear from those normal dungeons and scenarios is meant to get you into LFR (no word on if heroic dungeon gear will actually be better than LFR.)

Heroics are going to be more of a challenge than normal dungeons (obviously,) and likely more difficult than Mists heroics, but the hope is that they will not be "brutally difficult" (I'm looking at you, Cataclysm.)

After quickly running over and doing the tank silver challenge on Jarsus, I think that this could, potentially, be quite nice. So often I come across people queued as tanks or healers that clearly don't know what they're doing, so it should be quite nice to set the bar a little higher for entry. Just knowing that, say, a tank cannot pass that test without being able to pay attention to multiple mobs, and be able to position and taunt, it forces everyone to at least learn the very basics.

Admittedly, there will be situations where those basic skills need to be combined in unusual ways, and I'm sure Proving Grounds won't work perfectly, but given that it's a reasonable challenge - not face roll, but not Kanrethad Ebonlocke level - it seems like an exciting solution.