Vampirism in TESO, in my opinion, is lack luster. It is a bit of a missed opportunity to make an awesome skill line and an awesome looking transformation that bases themselves off of what they did in skyrim, just like they did for the WW. With that said here is my suggestion to what I think the Vampirism skill line should be.
Vampirism
Ultimate: Vampire Transformation, 325 Ultimate
Assume your ultimate form, transforming into a floating vampire fearing nearby enemies for 3 seconds. While transformed, your light and heavy attacks are replaced with blood magic at a maximum range of 28m. Your light attacks deal [X] Magic Damage and your heavy attacks deal [Y] Magic damage over 8 seconds.
While slotted your Magicka Recovery is increased by 15%. You also ignore your movement speed penalty while in crouch.
Using Vampire abilities increases the duration of your Vampire form for 4 seconds. During nighttime, you can permanently be in Vampire form.
Morph 1: Vampire Lord (applies lifesteal)
Your light attacks apply minor lifesteal for 8 seconds, every 1 second when damaging the enemy.
Morph 2: Vampire Leader (Your heavy attacks do more damage over time and stuns your enemy)
Your heavy attacks apply a stronger drain, dealing [Z, Z>Y] Magic Damage over 8 seconds. Once hit they are stunned for 3 seconds.
Imagine this as a base line look for it but make it in "TESO style"

Abilities:
Ability 1: Vampiric Sight
Attune your eyes to your new vampiric form, revealing stealthed and invisible enemies within 6 meters around you for 5 seconds. Exposed enemies cannot return to stealth or invisibility for 3 seconds
Morph 1: Terrifying Sight
Fear up to 3 nearby enemies for 4 seconds and setting them off-balance for 5 seconds.
Morph 2: Vampiric Seduction
You and your allies gain Major Sorcery, increasing you spell damage by 20% for 15 seconds.
Ability 2: Vampiric Grip
Crush your enemies in front of you with your grip dealing [X] Magic Damage and an additional [Y] Magic Damage over 10 seconds
Morph 1: Vampire Talons
Targets effected suffer Minor Breach, reducing their spell resistance by 1320.
Morph 2: Gargoyle’s Talons
This ability instead deals frost damage and immobilizes the enemy.
Ability 3: Bat Swarm
Darken the sky with a cloud of bats, dealing [X] Magic Damage to nearby enemies every 2 second for 8 seconds.
Morph 1: Devouring Swarm (the magic damage I suggest here is a similar amount to solar barrage ability of the templars, less then what the current ultimate of vampirism deals. In the meanwhile, the time is increased to 8 seconds from 5 seconds and the damage is every 2 seconds instead of 1 second, granting vampires a pulsing AOE)
Each enemy hit heals you for [Y] health.
Morph 2: Empowered Swarm (this morph increases the damage and duration)
The bats deal [X+Y] magic damage to nearby enemies every 2 seconds for 10 seconds.
Ability 4: Raise the Dead (cast time 3 seconds)
Reanimate a nearby corpse in the form of a Thrall to fight besides you. This thrall deals [X] Magic Damage. You can activate the thrall again causing it to go in a frenzy dealing [Y] Magic Damage in a conal area for 4 seconds. You can only have 1 Thrall at a time. Cast time is 3 seconds.
Morph 1: Corpse Curse
Grants a synergy to allies causing the thrall to explode, dealing [Y] Magic damage to all enemies within 6 meters.
Morph 2: Empowering Dead
The Thrall deals an additional [Z] Magic damage over 6 seconds with his base attack.
Ability 5: Mist Form (same as what it is now in the game)
Dissolve into a dark mist, reducing your damage taken by 75% for 3-4 seconds.
Entering this form removes and grants immunity to all disabling and immobilization effects, but you cannot be healed and your Magicka Recovery is disabled.
Morph 1: Elusive Mist (same as what it is now in the game)
Grants Major Expedition, increasing your Movement Speed by 30%.
Morph 2: Escaping Mist
Teleports you forward 15 meters. You stay in mist form for 1second after teleporting forwards.
Passives:
1 – Blood Ritual - STAGE 1, unlocked at level 1 Vampire
Allows you to infect another player with Nxiphilic Sanguivoria once every 7 days by returning to the Vampire ritual site.
Players already infected with Lycanthropy cannot be infected with Noxiphilic Sanguivoria.
2 – Supernatural Recovery (while in Vampire Form, unlocked at level 3 Vampire)
RANK 1: Increases your Magicka Recovery by 3% and your heavy attack Magicka return by 25%. - STAGE 1
RANK 2: Increases your Magicka Recovery by 5% and your heavy attack Magicka return by 50%. - STAGE 2
3 – Undeath (while in Vampire Form, unlocked at level 5 Vampire)
RANK 1: Reduces your damage taken by up to 15% based on your missing Health while you are below 15% Health. - STAGE 2
RANK 2: Reduces your damage taken by up to 30% based on your missing Health while you are below 30% Health. - STAGE 3
4 – Unnatural Strength (while in Vampire Form, unlocked at level 7 Vampire)
Reduces the severity of the Health Recovery determent in Vampirism stages 2 through4
RANK 1: Increases your Spell Damage by 9% and increases your Spell and Physical Resistance by 2500. - STAGE 3
RANK 2: Increases your Spell Damage by 18% and increases your Spell and Physical Resistance by 5000. - STAGE 4
5 – Power of the Grove (while in Vampire Form, unlocked at level 10 Vampire)
RANK 1: Reduce the cost of your vampire abilities by 3% for each transformed vampire in your group, including yourself, up to a maximum of 12%. - STAGE 4
RANK 2: Reduce the cost of your vampire abilities by 5% for each transformed vampire in your group, including yourself, up to a maximum of 20%. - STAGE 4
Stages:
The vampire stages I suggest a little different:
- Each last 6 hours, but casting any Vampire ability will advance this timer by 30 minutes.
- Feeding as a Vampire will
INCREASE your Vampire Stage by 1: I never understood why TESO made it so that when you feed you become a "weaker" vampire. This way the more you feed the stronger you are, as a true vampire should be.
STAGE 1 - 35% Flame Damage taken, 0% Vampire Ability cost reduction, 75% Health Recovery reduction, 0% Frost Damage Reduction.
STAGE 2 - 35% Flame Damage taken, 7% Vampire Ability cost reduction, 50% Health Recovery reduction, 10% Frost Damage Reduction.
STAGE 3 - 25% Flame Damage taken, 14% Vampire Ability cost reduction, 25% Health Recovery reduction, 20% Frost Damage Reduction.
STAGE 4 - 17% Flame Damage taken, 21% Vampire Ability cost reduction, 5% Health Recovery reduction, 30% Frost Damage Reduction.
Difference here is, as I said above, feeding will increase your stage making you stronger and making your weakness's less prevalent. This gives you more benefits the more you feed and less benefits the more you starve your vampirism (which realistically, a starving vampire is weaker).
With these suggestions for the skill line I wanted to accomplish a couple of things:
1 - Makes its use more DPS then tanking. This way, the Undeath passive that currently exists won't be so used for tanks in PVE. This also means that PVP players won't have this big passive as easily accessible since you need to be in vampire form to have access to them.
2 - Finally gives Vampirism a transformation similar to skyrim's but with a TESO design to it. This makes it look cooler then the non-transformable vampire that we currently have.
3 - Removes peoples ability to walk fast while in crouch since the Dark Stalker passive is no longer present. This is a fortunate/unfortunate change to many but will allow a more diverse use of swap sets or gank sets in PVP.
4 - Gives you similar buffs that a WW has but usable for a magicka character.
What do you guys think? Let me know in the comments.