ive seen a few posts and know that people including myself are worried about the speed of progression through the current 12 available raid bosses. yes in one week they have all been cleared... but just keep in mind these guilds have done all this countless times already in the Beta, they have every strategy down, every mechanic already grinded into their mind. take your own guild into blackwing descent today and you will wipe wipe wipe wipe.... (getting gradually closer to kill of course) then kill maybe after an hour or so of wipes, thats 1 down... and it only gets harder. so yer relax. its not like WoTLK like ive seen some people say, because unless your on the top 5 guilds servers you havnt seen any realm firsts yet in raids, like you wouldve at Wrath.
The only thing really hard about the first set of bosses for each entry raid is that our gear sucks, and normally simple mechanics are made harder since everyone is strained to do their best with what little we have.
Give it a month or so, when people start downing a couple bosses, it'll snowball, and people will catch up quickly.
That said, our first night of attempting BWD, we nearly downed the ODS, and Magmaw, with wipes in the teens percent on both. If we had Beta experience, I bet we could do them too right off the bat :P