From what the leaks showed, to have mounts on WvW either we are going to need PvE masteries (which means WvWers need to PvE a lot to get it all – thus not what WvW players want) or a specific WvW ability for it (something that would make new players on a disadvantage and ANET has already been very specific they don’t like this when they removed the guard stacks). So this is already a point against it.
Next you would implement it only on DBL? Why? I don’t event think they are able to make this distinction for just the DBL and to top it off, you would basically lose stuff when going to ABL or EBG.
Third, mounts will need to be something more than just “skins” so either it gives more speed, movement options or abilities, so now you may have shortened distances and made the DBL smaller and the ABL diminute or create a whole new balance mess.
Fourth, ANET would need to make a support for a whole mechanic of fighting on gliders and mounts – with all the difficult balance that would entail, otherwise gliding / mounts = free bags to the other team.
With all they are probably working on to make huge maps, stories, specs, mechanics, etc you really think they will have the time to do this extremely complex set of stuff when WvW has a lot of bigger problems and if done improperly this would only add to the list of problems?
