My personal experience is that the healer / DPS really set the pace for the dungeon.
As a tank, sure I go first ... but its upto them to do the majority of the actual killing of crap. In an Ideal world that is. I've found with DF that alot of the time I'll out DPS them (as a paladin sadly) and so the pace of the dungeon is really out of my control. Yes I'll pull the next pack right away (Honestly the ONLY thing I look at is healer MP, healer has 60%+ I'm good to pull) but when it takes 2mins+ to kill a pack of mobs ... well I cant be held accountable for that.
To be fair, its *very* rare that I use RoH combo on a paladin. For most run's I wont use it at all. DPS are just not even in the ballpark of pulling threat from me. Generally any pack of 5+ Mobs I'll be in Shield Oath for (Although I do use full str right side) and bosses I'll start and stay in Sword Oath for. Thats not saying *all* the DPS I get are wank .. just today I had a Bard unload on a fractal boss and snag aggro from me, awesome !!! A RoH combo and we were good. That said on the other bosses I did weave in a couple of RoH combos (Esp that stupid Mino since I move from his 360 swing) and we were golden. When I get great (Hell even good) DPS a dungeon run is fast. When the DPS is slacking it takes longer, hell theres only so much I can do as far as DPS goes /shrug.
Like other tanks here, I take the first pull as a guage to how many I should be pulling from there on. So if you slack on the first pull, expect me to pull light from then on.
People have mentioned Trees and Bees, generally I pull all of them, I do pay attention though and Hallowed / CD as required. I have to say *most* DPS are really good and focus down the Bees correctly, then I'll just drag the tree up the hill and kill it with the 2 totems and Vanu up there. Its rare that DPS dont kill bees first ... CD's will carry you through it though.
I've been pleased to see more and more Healers doing decent DPS now though, thats speeding runs up. Not all Healers DPS and its not something I *expect* of healers, Just really nice to see them laying in some hurt on pulls, makes me feel good about my CD usage that they are comfortable enough to CS and throw out some DPS between heals.
Bottom line though, tanks pull and hold hate, do what DPS we can. The overall *pace* or *speed* of a dungeon comes down to how fast crap dies .. and thats all about DPS. DPS players, Healers doing DPS and tanks pushing as much DPS as poss. When you get a group that does that its a fast run, for each part missing the run slows more and more. So in conclusion .. fast runs are not just about the tank, its a group effort.
And if a tank stops and stands infront of a boss ask him why if it bugs you so much. I know I did it yesterday, Healer was great and throwing out a ton of DPS on trash, mana management may not have been his strong suit though, so we hit the boss with him at 2K mana, so I waited until 9K (About 70%) before I pulled. No way was I irritated at the healer though, the 15s we had to wait was easy made up on the kill times from his added DPS on trash /shrug.