Introduction: Why Vladimir
Vladimir is a great champion for Dominion. Why? because he's tanky, and unlike most AP champions, he directly benefits from becoming even more tanky from his passive. He easily surpasses many AP champions in Dominion for this simple fact. In addition, his AoE mini-nuke; Tides of Blood, his ultimate and his blood pool make it very difficult for a group of enemies of any size to capture a point from him. Combine that with Garrison and Vladimir becomes a point defending master
This rune set up is what I've found to be the most effective. This gives you as much health as possible (with a healthy bonus to AP from his passive.) I choose to use the level scaling runes simply for the reason that in Dominion, your champion levels up quite rapidly, so you benefit from the leveling runes very quickly. Since the level scaling runes become more effective than the flat amount runes by around level 8, you've got a more powerful champion by about 5 minutes into the game.
Fairly simple here. As tanky champions have the edge in Dominion, putting the majority of your points in Defense will help you last that much longer when defending or capturing a point. The 9 in Offense simply helps you do a bit more damage, 15% magic pen is always good.
It's not out of the question to go with a 9/0/21 build for the CD reduction and move speed, but I honestly find that being as tough as possible is hard to pass up for a Dominion build.
I start with a Kindlegem, boots and a couple health potions. I typically take the bottom point, so the bonus health and CDR helps to dominate the person the other team sends down there.
Next comes the Sorcerer's Shoes, Spell pen is great, especially coupled with the passive bonus from the Crystal Scar buff you get from playing Dominion. You can get whichever boots you like, CDR boots are a great alternative if you'd prefer. Personal preference is all it really comes down to here. Mercury treads or Ninja Tabi are situational choices as well, don't hesitate to buy these if the other team is killing the hell out of you.
Haunting Guise is a great item to pick up early. Any item with AP and HP is great on Vlad thanks to his passive, which if you don't know, gives health from AP, and AP from bonus health.
Next is to turn the Kindlegem into a Hextech Sweeper. Now this item was tailor-made for Vladimir. It packs good HP, decent AP, cooldown reduction and interesting passive and active abilities. With the passive ability, you can keep an eye on sneaky stealth characters. The active can be nice too, pop it in Akali's pool and watch her squirm. Not to mention the passive procs on Tides of Blood, so you have a chance to accidently reveal stealthers trying to make a sneak attack. You can alternatively use the Kindlegem to make a Spirit Visage if you want to cancel out the healing reduction debuff from the Crystal Scar aura. I would only recommend this if you want to go with a Spell Vamp build. But since this build focuses on a large amount of HP, it won't be totally necessary to heal yourself through spell vamp.
Next up: Rylai's. This item is perfect on Vlad. A great amount of HP, and straight AP provides some great synergy. The slow combined with the passive on you Sweeper will keep enemies in range and in sight. I can't stress how perfect this item is on Vlad.
Next is the Warmog's and Deathcap. Pretty simple, lots of HP, lots of AP, you'll be hard to kill, and you will hit like a truck. Games don't generally last long enough to get both, so you'll have to choose which one you want first. Warmogs if you're getting pwned, Deathcap if you're pwning, simple as that.
Pros / Cons
-Tanky through a large HP pool and good starting defense stats.
-Hard to kill thanks to Blood Pool, which is a huge advantage on Dominion where the object is to stay alive and defend your points.
-Decent sustain thanks to transfusion, although the healing is reduced on Crystal Scar.
-Doesn't have much of a chance against tanky AD champs which are all too popular on Dominion
Overall he's strong on Dominion, he can defend like a boss and can't be killed one on one by most champions. He's probably one of your best choices on Dominion as far as AP champions go.