What's the best way to powerlevel a team of 5?

[Undeadlord]

Obviously you cannot boost 5 at the same time, when defining "boosting" as a way that a high level character is pushing you through instances.
Blizzard nerfed pretty much all possibilities to abuse the mob tagging system in the open world.

You still could just play your 5 man team and using natural or quest related hyperspawns or simply do instances; you still have a severe advantage when it comes down to just grinding your way up.

Second option would be to boost a 4man group twice, while the 1st team includes a mage that's pushing the 2nd, leaving you with 2 60s on 3 accs and 1 on 2 accs.

What about doing instances with a 6th member as a raid? does it reduce your exp gain by a lot?

I was considering outdoor mob tagging, is not viable anymore? what do you mean they nerfed it? I wanted to snipe outdoor elites with hunter's pet.

What if I boost 4 members of my team to X level and then switch the powerleveler for the 5th member leaving it to catchup over time. Eg. I have a WWWWS team, I powerlevel x3 warrior + Shaman to 40 and leave 1 warrior behind. How long will it take for the warrior to catchup with the rest?