Vampire is less diverse and interesting than Werewolf in terms of ability choice and ultimate. Right now, the Vampire skill line is only good for a few passives and that's it. In a future DLC, ZoS could change that and take some time to overhaul Vampires:

First and foremost, casting Vampire abilities or the Ultimate in cities is now considered a Criminal Act. Unlike the Werewolf, Vampire skills can be used outside of VL, but while transformed your vampire skills gain an additional effect and are more potent. While transformed, the VL can only use their Vampire abilities and their melee attacks deal magic damage and afflict enemies with Major Lifesteal for 2 seconds. Please note that all values listed below are simply placeholders to illustrate the effect.

Vampire Ultimate: Changed to "Vampire Lord Transformation"
Vampire Lord gets increased max Magicka while active.There is no "devour" mechanic with Vampire Lord - you sustain the timer by killing and remaining in combat. The timer is adjusted for this. Initial time is 30s. Transformation timer is increased by 4 seconds if you are in combat every 5 seconds. Killing enemies while transformed grants 4 seconds.

Morph 1: A cloud of bats circles you while you are transformed, damaging enemies in melee range and healing you for the damage done.
Morph 2: Summons 2 friendly Gargoyles. Enemies struck by Gargoyle attacks are afflicted with Minor Maim and Minor Lifesteal for 15 seconds. Gargoyles respawn after 10 seconds if killed.

Three new abilities are added to the Vampire skill line:
Sanguinate: Draw on the power of your vampiric blood, healing for [15000] over 20 seconds. If transformed, you also gain Major Sorcery for the duration.
Morph 1: Adds a burst heal for [5000] on initial cast.
Morph 2: Decreases the cost and increases the heal over time.

Desecrate: Corrupt the ground with your blood, dealing [1800] each second to enemies in a 6m radius for 12 seconds. If transformed, you can have an additional patch of blood active at the same time.
Morph 1: Increases the radius to 8m. If transformed, deals additional damage each second.
Morph 2: No longer deals damage. Instead grants Minor Protection and heals you and allies standing within the blood patch. If transformed, also grants Minor Vitality.

Blood Warp: Launch yourself as a sinewy streak of blood and lash out at an enemy, dealing [4000] magic damage, healing yourself for 20% of the damage dealt. Deals increased damage based on the distance traveled. (22m range)
Morph 1: Decreases the cost and heals you instead for 40% of the damage dealt over 2 seconds.
Morph 2: No longer heals you, but after initial hit, the target takes an additional [7000] magic damage over 5 seconds.

The only change to the passives:
Savage Feeding I/II: Replaced with: "Your healing with vampire abilities is increased by up to 10%/20% in proportion to the severity of your wounds. While transformed, you gain an additional 4/8 seconds to your transformation when you kill an enemy, every 15 seconds."
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The idea behind these changes was to make vampire a powerful, regenerating threat in the thick of combat. Again, these suggestions may need adjusting but the goal of the post was to illustrate some ideas for making the Vampire skill line more interesting. I had also considered increasing the fire weakness while transformed given the fact you get much more power in that Ultimate form. but I'll leave it up to discussion.