I'm doing all quests as well. Bitching the whole time on collection quests lol. I'm 73, nearing 74. I've finished all quests in howling fjord and I'm about 75% through Dragonblight.

I run the dungeons when I feel my level is decent.

So far I've done a few dungeons.

Nexus. Done at 70
Ormorok . Tank and Spank
Telestra. Tank and Spank until you start flying around the screen. Put some flame shocks on her and thunderstorm when you get pullec close to her
Anomalus. Tank and Spank until he's immune, kill the add, rinse repeat until he dead.
Keristrasza. Set everyone up in a circle to release him. Blew all cooldowns, 5 fire elementals, trinkets, heroism, best dps (lower survivability) gear on and blew him down. The dot killed us all but he died too.

Utgarde Keep. Done at 70
Prince. Tank and Spank, thunderstorm adds
Skarvald/Dalronn. Kill Skarvald then Dalroon. Pretty easy.
Ingvar. Spread out in circle. Pop elementals (mix match of earth/fire). Waited until timers were down to 20 seconds until they despawn then pulled. Killed him for 1st phase without cooldowns besides ele's.
Before he got rez, I dropped elemental's again for fresh batch and popped EM/Trinkets/Hero to blow him down.

Azjol-Nerub. Done at 72
Krik'Thir. Pulling the adds in front starts fight. Not too hard, just blow through big guy first and drop stoneclaw's for first/third batch. 2nd batch you won't have stoneclaw cooldown up. Blow ele's and cooldowns on boxx. Pretty easy if you can last through the adds.
Hadronox. Pulling the guys starts the fight, take your time though. Kill the first pack, 2 more packs come out, but don't come at you. Randomly a mob non elite will come up, but you can rest between each back. Much more elaxed then first boss. Don't take too long, the boss fights his way up to the top once you pull that first pack. You can see him at bottom. I basically just killed the packs fast without resting, then rested to full mana and boss was at top attacking a crap load of bugs. He was at like 50% and i popped ele's and cooldowns and blew through him pretty easily.
Anub'Arak. Make sure you go inside the circle or you'll get locked out and can't dps him. Just spread out. dps till he burrows. Kill the adds. continue dps'n him when he unburrows and heal when needed. The spikes are annoying but overaul don't do that much damage. Drop stoneclaws if you are low on health for the add phase so you can heal back up before u dps them down.

Anh'Kahet. Done at 73. (right after I finishec Azjol)
Elder Nakox. Sat in doorway in view and casting range so the adds would come in front of me and not to my rear. Popped elemental's at start (mix and max) but waited until they had 30 seconds left before I pulled. This allowed me to pop them a 2nd time half way through fight. He hits fairly hard so without doing it this way I wasn't able to take him down. Just kill the guardian bug when boss goes immune and continue dps. The non elite adds will die from thunderstorm/ele's..
Didn't have a chance to finish up instance. had to repair by time I figured out how to knock down first boss and was pretty tired so hit sack after repair

One thing for sure is the instances seem to be faster in general, but also a lot more mobile files compared to bc.