Just to get this out of the way, I own PoF, I am not trying to beg for free stuff.
The thought occurred to me that players from other MMOs are used to having a mount of some form in the game, one that they can access without having to pay for anything extra. People coming in blind to gw2 will see people running around on cool raptors and energy dogs, and think hey this game's version of mounts are pretty cool, can't wait to get one. eventually learn that the only way to get them is via downloadable content, which I imagine will probably put a damper on things. Further still they will find there is no way of getting any kind of mount without paying extra, not even a basic one which has come to be a standard in MMOs. I think adding some kind of core mount will benefit player retention.