You've always been a fairly decent poster on here Rainfire, so i won't be too harsh on you, BUT you're over reacting to this (aswell as Xelnaga) It's a feat of strength, not an "achievment." It's not going to be sitting there in your achievment list mocking you with it's unobtainable presence, it simply won't exist unless you were in the closed beta.
It's a feat of strength relating to basic luck. If you weren't lucky enough to get an invite, then tough luck. If you were, congrats, you get a pointless accolade that recognises your luck.
Sure it's a douchey move on Blizzard's part to go back on their word, but are you really surprised? This is Blizzard we're talking about; the company that likes to contradict itself every other week.
You didn't really contribute anything special on the open weekend either, the game was at the end of it's testing. The servers were full to the cap whether you joined in or not, so it wouldn't make sense to dole the same achievment out to everyone that participated in the horrible experience that was the open weekend.
This is the biggest problem I have with games' "achievment" systems, people are so used to being "rewarded" by shiney boxes when fulfilling a certain criteria, people have been conditioned to be the same as the test-pigeon hitting a coloured square of light for a reward. The problem comes in when you (the pigeon) have the light removed, and the source removed, the perceived injustice of this makes people angry.