Guild Wars 2

With Heart of Thorns Anet introduced a great idea that was mobile fields. So far 5 professions out of the 9 have access to them:
Mesmer: Tides of Time (ethereal field – shield #5)
Ranger: Rejuvenating Tides (water field – celestial avatar #4)
Warrior: Flames of War (fire field – torch #5)
Revenant: Field of the Mists (dark field – hammer #4)
Engineer: Reconstructive Field (water field – medic gyro toolbelt)

Here are a few suggestions that Anet could add to the other professions:
Necromancer: Nightfall (dark field – greatsword #4)
Thief: Smoke Screen (smoke field – deception utility). It could be changed so it acts like Revenant’s Field of the Mists. It could still be used as a source of blasting for stealth too.
Guardian: Symbol of Swiftness (light field – staff #3). No longer would you have to stand still to gain the full amount of swiftness from this skill or place it carefully to gain 2 procs from it whilst on the move.
Elementalist: Ring of Fire (fire field – dagger #4) Fun to combo with various movement skills. Maybe add damage for when a foe moves through said field on top of the burn.