Am I uninformed? The game is in place. They are not making a new game from scratch all they are having to do in essence is port it over to a newer database and other tweaks. While this isn't exactly minor it is nowhere near as bad as designing everything from scratch. The zones, raids and all the other stuff that makes up the game is already done. It is more about getting it to run on blizzards current infrastructure and modern computers that is 95% of their task. Design choices are comparably minor and easy to implement once this is done.
As for subs on retail, you understand don't you a lot of veterans who are wanting to return for classic really won't care about retail. Those in retail who will try classic will likely split time if the sub includes both. I also said around the same time be it a few months apart. So next time before you come in claiming how uninformed I am you might want to do some research yourself.