Advice for emblem-gear-fueled dungeon speed runs

I don't think it's a controversial statement to say that the new emblem system has changed the face of the five-man dungeon scene, making it near unrecognizable compared to what it once was. Heroics these days are more comparable to running Scarlet Monastery at level 60 than Blackrock Depths. It's safe to say that much of we thought we knew about five-man dungeons has changed, and new assumptions need to replace old ones if we are to evolve to face the new challenges (or lack thereof) that await us on the other side of those instance portals (now replaced by an interface). Many have made these changes subconsciously already, but some may have avoided heroics during this time of great change, and this guide is for them. Note: This guide only applies to heroics, and only to the original Wrath heroics. The advice bellow doesn't apply to raiding or The Frozen Halls.

Tanks:
-Focus on whatever the DPS is attacking.
When it comes to trash, kill order is mostly meaningless these days. As much as you may want your DPS to attack the healer first, you will encounter DPS that just won't want to do it. Rather than getting worked up over them, it's better to just go along with it and focus on causing threat to the enemies they are attacking. Why? Let's say you focus on causing threat to the target you think should die first. This makes it easier for the DPS to over-aggro, so you will lose control of the mobs, making the battle slower. If, however, you focus on what the DPS is focusing on, you stay in control on the situation and the mobs will die faster, making the run faster, and because the mobs won't be running around doing damage to everyone, the run will be more enjoyable in general.

-Focus on AoE threat while fighting trash.
Back when kill order mattered, you would try to cause the most threat to the enemy highest on the kill order while not causing too much AoE threat because your DPS would be focusing on the target of highest priority and not trying to cause massive AoE damage. These days, DPS just want to AoE everything down, meaning if you try to focus on causing most of your threat to one target, you'll end up only holding on to that one target. Though you should use your auto-attacks to cause extra threat to whatever your DPS is attacking (as per the previous piece of advice), you should focus on using your AoE abilities rather than your single-target abilities.

DPS:
-Try to attack what the tank is attacking.
The tank losing control of trash is bad. Sure, with the kind of gear you're wearing, you can probably afford to take a few hits, but if the tank can't keep control of enemies, he can't cause as much damage to them as he could otherwise. As such, the run will be slower. The tank will be causing the most damage to his target, so it helps to focus your attacks on whoever your tank is targeting. You can turn on target-of-target in the options menu to make this easier.

Healers:
-Do some damage if you don't need to focus all of your time on healing.
If you and the tank are in great gear, you probably don't need to spend all of your time healing him and the group. In the olden days, it was considered unthinkable for healers to do any damage to enemy targets. After all, they need to heal when people take damage, and healing causes threat. The DPS can stop doing damage if they cause too much threat, but healers don't have that luxury. Extra threat was just something healers didn't need; it was something they couldn't afford. These days, however, you'd be lucky to break 1% of the tank's threat in an average heroic run. As such, consider dropping some damage on your enemies to make the fights go faster. This will be easier for Priests and Shamans than for Druids and Paladins, of course, since Druids need to leave Tree of Life to do damage, loosing a healing boost in the process, and Paladins can't do much damage without entering melee range, but Priests and Shamans should definitely consider dropping the odd offensive spell when they have nothing better to do. If anything, it will make the run more fun for you while you wait for your tank to drop bellow 95% health.

-Forgo mana efficiency for spell potency.
If you out-gear heroics and are rocking tier-nine or ten gear, you don't need to worry about mana. You do, however, need to worry about wiping. Heroics have become so easy these days that players simply have no patience for wiping. Now, granted, wipes are a near impossibility these days, but you still don't want them to happen. An unexpected development (adds, runners, etc.) can cause a sudden influx of damage, even in these heroics that we have all run before, so you need to stay on top of your game. In fact, being so comfortable with heroics likely leads us to make mistakes we would not have made in the days when they were difficult, if only because of sloppiness. Anyways, your main goal is to avoid a wipe, and knowing that running out of mana is a near impossibility unless you are blatantly overhealing everyone, you should feel free to use your larger, more expensive heals to reduce the chance of a wipe to near zero. It may feel wasteful, but it's only wastefulness if you can run out of whatever you are using.