Elusive mist VS Poison Mist.

So I have 2 choices here I can either go for a 45% movement speed which does sound amazing, or a 4 second poison 5 meter AoE that does damage (81) per 0.5 seconds (648).
I'm having an extremely hard time deciding because although I'm not pvping right now level 50 is creeping up (3 more levels) and I'd really like to give PvP another shot, since my first time at level 22 didn't go too great.
My problem is will bolt escape/lightning form be enough to make sure nobody hits me or will I need to get another 45% speed boost too? Or will a powerful AoE be any good at all? It seems AoE around your avatar as a sorc sounds strange but could someone talk me out of it because I'm leaning towards it.

Thank you community