As raidleader of a semi-casual 25 man raiding guild I can tell you that this raid is not easy nor very hard. I think its well balanced. A normal 25 man raiding guild that hasn't done the raid on the PTR probably didnt clear it on normal in the first week and thus needs atleast 2 resets to clear it on normal. If i remember correct alot of raid instances were cleared on normal in just the first reset. My guild has 4 out of 6 down on normal and I heard Eregon or w/e he is called is not easy at all.
In short, the difficulty is fine! Don't look at the top guilds as they raid like 10-15 hours per day 7 days a week AND have done/tried it on the PTR.