Well, those stages are pretty much what we're doing (Although we're focussed more on killing the pylons *close* to one another than killing them as fast as possible, due to the haste buff - not that that adds much time on it.)Acidote is mostly right. Getting four orbs down is crucial. However, I would also go so far as to say the pylons need to be downed quickly, as well. The faster those go down, the less adds that spawn afterwards, which means more focus on the boss. Not as critical as four orbs, but I feel it is pretty important to overall success.
As I've indicated, I think our only real problem is locking down P3, but I'm not sure if there's much more we can do there in terms of healing other than pushing hard. I think we'd really have struggled yesterday if we didn't also have a druid offtank who could heart-of-the-wild heal in that final phase.