I'm honestly still on the fence post about it. Both arguments for and against mounts are valid and have some pretty even pros and cons.
I say it often, "if they don't add mounts soon I'm going to slap a saddle on a Quaggan and ride them around." But, what if they do add mounts of some kind with say.. 40% run speed? How would that change the game?
The knee jerk reaction is that it won't affect the game. As an Elementalist I can get close to that speed near permanently if I stay in Air. Other classes can get close but very temporarily. So given that we can go fast temporarily how could a mount change the feel of the game? Very easily.
How fast you move on the ground changes the scope and feel of the environment around you. The world of Tyria feels massive when you're running around all slow (especially on a Norn) but if you're always running fast, suddenly the world begins to shrink and you begin to miss out on a lot of the world around you as well.
An example that may be hit or miss for some, back in World of Warcaft, in the Burning Crusade expansion, we got flying mounts. This was awesome but it had some unintended consequences. Suddenly I could fly high, avoid all mobs on the ground and just jet to where I wanted in not time at all. Literally, no time at all from one side of the map to the other without flight paths because it was cheap, fairly fast and without aggro.
Sounds great, right? But think of what I missed in doing so: gathering nodes, mob exp/loot, named spawns, etc. That all sounds like an inconvenience when all you want to do is get where you're going without trouble but that's what you have a flight path for, to save you that trouble and to be a money sink.
So what does all that mean for Guild Wars 2? If we're given mounts our world will shrink and it will take away from the basic rewards of exploration which is so key to the gameplay. Ground mounts with 40% or so speed won't pose a Point A to Point B problem as it did with flying mounts; you'll still need to fight mobs if you get dismounted in combat, can still gather, etc but it will reduce, though not substantially, our Waypoint money-sink.
However, if implemented right (and only for PvE), I think mounts can do a lot of good, too. I would like to see mounts be given as a buyable option of fair expense (50g or more perhaps, account bound) to characters who have achieved 100% map completion on at least one character. It could be argued that making it account bound will lead to it being abused by players and botters alike but my logic is this: if the mount requires one level 80 character with 100% Map Completion and a good deal of money to buy one for that character and then alt characters, that's a considerable money-sink that I highly doubt will be very attainable for a majority of players. Mounts will offer experienced players not only a faster way around but something to work for and spend money on (as well as real cash for possible Gem bought mount skins), as well as collection possibilities of different mounts.
In the end, I can see the reasoning both ways. I would love to see them implemented for Map Completion but I would be just fine if they're never put in at all.
