Increase range of our teleport skill (Lightning Flash) from 900 to 1200 - I'd say remove the damage portion of this skill to compensate (since I only ever use it for positioning/running/chasing), but I'd probably kitten off some weavers. As a staff ele that can correctly guess 1200 range with my eyes closed, it's annoying having a skill that is 900 range since I usually guess the range incorrectly and I end up dying for it in pvp. Or I end up overcompensating for my bad guessing and end up only teleporting ~600 range. This change would also have no effect on pve.
Allow all skills to be cast while moving - This change would have next to no effect on pve, and would slightly improve survivability for the ele in pvp. I don't understand why this hasn't already been implemented, since all the ele skills that require the ele to stand still already have very long cast times and don't provide much burst damage. I'm also not aware of any other classes that have this handicap without access to stealth (though I admit, I haven't played very many other classes).
Improve elemental pet elite (Glyph of Elementals) - There are so many ways to improve this skill. Literally any of these options would help:
Reduce cooldown on fiery greatsword - A 3 minute cooldown? Really? For a conjured weapon that locks me out of all my other skills? And reduces my range down to 600? Just why? It's a small boost to my dps that I can only use when my enemy isn't paying attention to me or when I'm attacking a bunker. If it was on a lower cooldown, I could potentially use it as a means of escaping fights with the two movement skills it provides. But on a 3 minute cooldown, that's a complete waste. The cooldown on this skill should be greatly reduced (down to 1 minute imo).
Improve Rebound - I've made a post about this skill before, but I'll repeat it here. Unless I'm playing a support spec, the 2800 heal on rebound does nothing for me. I usually wait for the aura this skill provides after 5 seconds, but it's too hard to predict how the fight will change after 5 seconds. Given that tempest is already a kitten pvp class, it would be great if this skill immediately procced the aura as soon as it's cast. I feel like making this change would also move support tempest from a 2nd tier support spec to being on par with (and uniquely different than) the firebrand, which is what the developers said they were hoping to do with the ele anyway.