I played the free core game for quiet a while until I recently decided to buy HoT and PoF - since I knew I like the game. However - before buying PoF I already noticed that players with mounts have a huge advantage over F2P players that is way beyond the previous limitations and way more noticable. One could argue that free players should take it as is since they play for free. However I have a feeling that this way too noticable disadvantage will discourage players trying the game from actually upgrading to the full version because they are punished and discouraged before being able to find out how big and nice GW2 actually is.
Personally I suppose the best solution to this problem would be to have a basic mount ( slightly slower than the other mounts and with no special abilities ) available even to core players. This might also solve the no mounts in WvW problem ( unless the reasons for this are technical issues ).
Often I fail to correctly convey my point - so please be aware that my intention is not to criticize but rather to prevent GW2's playersbase to drop since we all have a more enjoyable game experience with a big enough playerbase.