Raid invites and achievements

A reader suggested I turn this into a separate discussion thread, which is an excellent idea. I was talking about my T9-geared protection warrior with 35k health unbuffed having problem getting into a raid.

Recently, in the streets of Dalaran:
[2. Trade] PuGRaidleader: LF1M tank ToC 10-man
Tobold: /tell PuGRaidleader Invite me, I'm a tank with 35k health unbuffed
PuGRaidleader replies: Link achievement
Tobold: What achievement?
PuGRaidleader: The achievement proving you completed ToC
Tobold: But I've never been there!
PuGRaidleader: Get lost, noob!

And it isn't just the hardest raids. This week on my server the weekly raid quest is to kill Malygos, and my tank couldn't get a pickup raid invite, because he didn't have the achievement of having killed Malygos before. Malygos certainly *used* to be a hard raid, but even then the problematic part wasn't the tanking, but the dps, and the flood of emblem epics certainly solved that problem.

What use is getting all those epics from heroics if you still can't get into a raid, even one you're overgeared for? I really think Blizzard needs to give their raid dungeon finder the same functionality as the 5-man dungeon finder, so we can get raids together without some overdemanding PuG raid leader kicking us out.