Holy Brick Wall Batman!

[Seldum]

I run 5x druids, with 3xboomkins, 1x resto and a bear. This is my first toons ever at 80, so no heirloom or early flying in NR for me

I have mixed up dungeons and questing in NR. Prior I only did quests with my team. I kept all the toons within the same lvl until around 74. Then I had a quest burnout. I actually stopped playing my team, and solo leveled my tank in instances, both to learn how to tank and to learn the instances.
My initial plan was to gear out the tank a bit, and then pickup the rest of the team.

I had so much fun with my tank, that I hit 80 and continued gearing him. Atm. he got a blend of iL200 and 245 gear, and I have picked up my team again. The only quest chain I did was the Wrathgate quest chain, the rest of the leveling went through the dungeon finder with my team.
I'm still a bit sick of doing quests, and from 70-80 have been the toughest leveling experience for me.

My original plan was to farm badges and stoonkeeper shards to purchase heirlooms for my paladin team currently at lvl 13, and then begin leveling them for the fun of it. But since it has taken me /played of 15 days to level my druid team, i'm currently uncertain if I want to pickup the paladin team - even though I have laughed so hard at the 5 paladins chopping away at everything, I never get tired of that.

Gearing my tank way better than the rest of my team, made the leveling in instances a breeze.

[Drommon]

Seldum,

I did the same thing as you did but with some differences. My tank is a warrior and he led a mixed team. About level 72 I got tired of questing so I BGed my tank to 80 and then I did heroics to gear him up. Then I instanced my team from 72-77 without a hitch but got bored of doing instances. In April I picked of my pally team (level 42 at the time) and I have been questing the whole time and they are now 76 level. 5xpallys are so much fun. I made them all shockadins recently and they just tear through stuff like nobodies business. Now I actually enjoy doing the NR collection quests. There is no downtime. Between level 68 to 76 I picked 16000 gold just from questing, trash and vendoring the quest rewards.

I didn't bother getting heirlooms for the pally team. All this tells me that party composition plays a role in how you want to play the game. I realized that I needed to do things fast, its just the way I am personally. The 5xpally team is homogenous in both race an class and was a snap to use and setup. Plus they smash stuff up!

So get on your pally team!