Experience and seeing how the healer handles an initial large pull tells me what succession of packs I will pull most of the times. Luckily in a lot of dungeons, with the exception of the packs leading up to the first boss, they're set in such a way you can pull up to a certain point where they have to die in order to advance and thus I know I'm comfortable more often than not with pulling to that point and coping even if the healer struggles. I also slow down if the Healer asks for it.
A lot of factors come into account of course, if your DPS are bad at cleaving and your healer struggles and isn't a WHM that provides the extra mitigation of holy, then pulling pack by pack vs wall to wall barely makes an ounce of difference to speed.