Heros - Should I use the Ele or the Necro for DPS? AND ...

Should I develop the Elementalist or the Necro for Damage-Per-Second?
What second profession should I pick for each, given that most of the builds I have looked at require careful thought to play properly (and assuming the automated heros don't strategize their actions like we do)?

I usually go for the brute force approach myself and use both an ele (Searing Flames) and a necro (minons). Although the necro serves more as a provider of expandable meat shields, the damage of the minions is not to be disregarded. As for the secondary profession, mesmer is always a solid choice. Just put some leftover points in Inspiration and give them Leech Signet and Power Drain. The AI sucks at prioritizing interrupts but it has incredible reflexes.

You're right. Do not give Heroes builds that would require them to think. A classic curses necro with echo / spiteful spirit / reckless haste... for example doesn't work well because the AI can't figure out how to chain the skills properly. A Searing Flames ele on the other hand is a no-brainer: basically all they need to do is spam Searing Flames.

The Ele Heroes work decently as self sustaining nukers, I personally run a Searing Flames build on mine. An example:

1. Searing Flames
2. Immolate
3. Glowing Gaze
4. Self Heal / Extra Attack Skill
5. Fire Attunement
6. Power Drain
7. Leech Signet
8. Res Sig / Hard Res

The Necro heroes are amazingly good at Minion Mastering, and I devoted one (In my case Master of Whispers) to MMing and the other to the Curses attribute line. An example MM build:

1. (Elite slot, I use Tainted Flesh often.)
2. Animate Bone Fiend
3. Animate Bone Horror
4. Blood of the Master
5. Taste of Pain
6. Signet of Lost Souls
7. Blood Ritual (Shift + Click'd Off)
8. Res Sig / Hard Res

Yeah, heros are outstanding minionmancers, but don't give them Death Nova. They spend all their energy constantly applying and reapplying Death Nova to the entire team and all their minions.

True, also they constantly lag behind when travelling around being too busy applying death nova to catch up. Often you have to flag them if you want them to actually join the battle.

The necro is very useful when MM, also nice with SV or SS when fighting Shiro or Varesh.

The ele is also good if you have at least one other SF in your team.

~Prof.