That's the problem with rumors is that even if they look right or get some things right that doesn't mean they are always reliable. Here's the problem with that rumor is that it came at the time around the start of season 3 and basically gave voice to all of the speculation that was running rampant at the time. People were calling alicorn twilight as soon as the special destiny thing was announced and twilight alicorn merchandise had been showing up, and the second part of the rumor has been proven to be false Hasbro has gone ahead with licensing derpy toys and merchandise well into 2013 as well as allowing her to return to the background for the season finale. That rumor while verbose only really states 2 things, one of which had been heavily discussed and hinted at previously and the other turned out to be false.

In the end, I'm sure Hasbro likes the idea of Twilight alicorn, but there is still nothing to prove that it was a unilateral decision on their part.