Se having old content still locked doesn't have to make sense.
Maybe they forgot or maybe they will get to it sometime before 3.0.
Or perhaps they just don't care cuz they can spend all that caring on how to execute 3.0.
Maybe they will change how they lock things in the future, maybe they won't.

Just bide ur time and save all the hooplah for 3.0 raiding cuz if ur in the "hopeless" situation atm then starting fresh into the raiding scene ( clearing content when its the "hot" new thing ) is probably the best approach.
3.0 is probably the make it or break it moment for a lot of ppl as the carrot on the stick, weekly loot lockout, 1 static raid group, tome gear is tiring them out.
Another year of this? Hopefully not.