I'm tired of people saying FiM is aimed at the brony and/or adult communities because of the in-jokes. There have been adult references and 'in jokes' in cartoons for little kids since the
dawn of time. FiM is NOT the first to do this. Heck, look at some of the cartoons from the 80's and you'll find tons of such references, including even political jokes (which surely would not have made any sense to little kids!)
FiM is just one cartoon that is cashing in on the current internet phenominon - the fact that it is now VERY easy for entertainers to communicate with their fans, and visa versa.
As for Celestia, this topic comes up on the Arena from time to time and I hear the same things each time, that the retailers want a pink pony, or that Hasbro thinks pink ponies sell better. I'm still confused though. Out of all the characters from the show that they have made toys of (all 6 of the mane cast, the 3 CMC, Luna and Celestia, and all the blind bag toys) Celestia is the ONLY toy they decided to change from white to pink. They didn't decide to do that with Rarity, and she's white! So I dunno, I just don't buy the whole 'they changed her so they could sell her.' Because following that logic, wouldn't they have made every character from the show pink?
And she's not even one of the main characters, it's not like she appears in every single episode like the mane 6 do. So changing her in order to sell toys doesn't seem to make much sense when they could have changed someone else who appears more often, Rarity for instance.
Maybe that's why Hasbro felt they could change her without too much backlash from their buyers? Because she doesn't appear in every episode? (Although she technically does if you count the opening, so now I'm stumped again...)
*shrug* I think this is one of those "the world will never know" sort of things...