As the forum didn't have any PvP builds for Magicka Sorcerer, I decided to share my own, which is a combination of different builds I found on the internet, adjusted to personal preference. Even though shields were nerfed quite a bit, with all the resistances you get from this build, you can make up the difference quite well.
RACE Dunmer, Altmer or Breton I personally prefer Dunmer, because of the Flame Damage bonus you get. Vampirism Stage 4 is highly recommended.
FOOD Witchmother's Potent Brew (Max Health, Max Magicka, Magicka Regen) or Clockwork Citrus Filet (the better version of Witchmothers)
MUNDUS The Atronach or The Lover - I personally prefer The Lover as it gives you more damage, but if you feel like you need more sustain, you can switch to The Atronach.
POTIONS You will want to use Tristat potions, as they will give you great sustain, Spell Power potions are also an option, but you might find yourself lacking stamina in prolonged fights.
GEAR You will want to use two crafted sets, Shacklebreaker and Armor Master.
Front Bar Inferno Staff - Master's Staff/Perfect Asylum Staff - Absorb Magicka - Infused
Back Bar Restoration Staff - Armor Master - Weapon Damage - Infused
You could replace the monster set with any other really, Blood Spawn though makes you even more tanky than you already are with Armor Master, as well as giving you access to one of your ultimates much more frequently. I actually removed Tri stats glyphs from big pieces after a while, to get to around 13k stamina, which is enough to me, especially if you're using the right potions. I replaced them with 2 Max Magicka Glyphs and a Max Health Glyph. The difference isn't much, but having a bigger Magicka pool feels better to me.
Destructive Reach/Crushing Shock (depending on the staff you are using)
Destructive Reach is much better than Crushing Shock in my opinion, as it's also a reliable stun, but the other should give you some more damage. You can swap Hardened Ward for Empowered Ward, which will give you more Magicka recovery, but less shield. I personally wouldn't recommend this, as Hardened Ward is your biggest shield, which is pretty good to have in the front bar. You can choose either Meteor morph, I like Ice Comet better becuse it's a 8 seconds 50% slow on the target. Can also swap ultimate with Atronach or Dawnbreaker of Smiting (all of them will help you kite meeles).
I have tried swapping so many skills in this bar, and these are the ones I'm most comfortable on, you could swap Healing Ward for Mutagen to get a more reliable healing, but you'd lose one of your shields, you could also use Harness Magicka instead of Dampen Magic to get more sustain out of it, but the shield you get is much weaker. Streak can be removed completly for any other skill, be it Power Surge, Mutagen, Ele Drain (for this one you'd have to move the Ward or Curse from your front bar), Rune Cage; but you'd lose the mobility that makes sorcerer in PvP so fun to me. It's also a pretty good stun as you don't really see the animation warning like Rune Cage. You can replace Dark Conversion with Power Surge to get healing over time, but in this case you'd want to use The Atronach Mundus because DC helps you to keep up the Magicka a ton. If you do use DC make sure you can't be interrupted while you're casting it tho, or it will enter a cooldown before you can use it again.
Dampen Magic combined with Armor Master, Blood Spawn sets and Boundless storm will make you really really tanky, so make sure you always have these buffs up. Resto staff Ult will allow you to face tank pretty much everything as long as it's running, and is really low cost.