Guild Wars 2

The conjure suggestion is a good one , i would like to see at least one more trait for conjured weapons.
The earth line is really really weak ,it will not be picked by almost anyone.
Soothing mist should be at least twice as potent in its regular form.
Lingering elements should be a minor somewhere.
I have read most of the class changes and i play all classes but i believe that ele will have a hard time facing most if not using one of the two meta builds that there will be.
I would like some stronger stuff for signets/glyphs cause they seem to be in game just to be not picked so that there can be an illusion of choices(you still can try them but meh..).

The warhorn idea seems very nice to me it would really fit tempest thematically.
There could be a very dangerous gameplay involved with tempest. My suggestions are mostly for utility skills.
Tempest can play with corruption style magic that promotes the recklessness of the tempest:
Utility 1: Summon a sandstorm that immobilizes you but blinds and bleeds foes.
Utility 2: Summon a whirlwind that follows your enemy at high speed and damages him , while this happens you are slowed
Utility 3: Apply 10stacks of burning to your enemy while you get chilled
Utility 4:(Toggle) Create a water nebula that dazes your opponents in a certain area while this i active you lose health
Elite skill: Transform into a state that makes your allies into a block of ice(invulnerable) while you apply torment, bleed and confusion to enemies.

Having a mastery bound mount on specific maps to aid you explore the terrain is a very fun and interactive idea that opens up the potential of a different playstyle than the one that we are currently used to and making the progression of leveling much more fulfilling.
It will give the end-game another dimension of achievement and bragging rights. Furthermore the use of mounts in hard to travel areas or inaccessible areas will result in a healthy variety of goals and choice on how we spent our mastery points by not having a standard order in which we complete them.

My personal suggestions on the matter are :
Make mounts that are connected with your profession. Example : rangers mounting a dire-wolf , elementalists riding an elemental , engineers riding a motorbike , thieves riding a shadow pony , necromancers riding some undead mount etc..

Secondly have some standard skills while on the mount and some for the specific professions. They do not have to be battle skills but more like useful skills. Example : Dire-wolf has fear , the elemental has mist form/invulnerability ,the motorbike can leak oil to knockdown ,the shadow pony can have stealth/mass blind ,the undead one can have mass immobilize.
This will add some fun mechanics to help you go around in maps or personal instances that have hordes of enemies or ambushes or even a special kind of adventure like a race in the jungle tied to an achievement.