Obviously you aren't using the same builds now as on the first page (IAU for example), but it sounds like you do both pits and wastes together as a full team. Would it not be quicker to do wastes & pits at the same time, with half a team in each?
Also if you want really fast times I suggest you start using E/A for the sliver tanks.
I don't really know how well this would work or if you have considered it already, but using an E/A in vale with stoneflesh, you can reduce the damage from IW to something like 2dmg / hit, which would then enable you to aggro several groups and sliver them.
A few pointers from doing duo/solo runs pre-nerf, most of these you are probably already doing but just to make sure:
4H: no need to clear plains, just have one tank pull all the aggro and other one take quest. If this quest can still be soloed that could save time, apparently it depends on when the silver webs spawn and how long they take to run down.
Vale: you can kill all graspings+pop reaper in roughly the same time with a sliver build as with a mesmer build by pulling everything into one mob and blocking on wall. During quest, the group of spirits on the hill die fastest if you aggro the 3 groups of coldfires and use them as fuel for sliver. Once quest is complete you can dcharge to the spider to lose aggro.
Pits: Kill everything in two pulls, first is obvious at the bottom as that group doesn't pull far, 2nd pull you go across the terrors and pull threshers + back group into them (although I don't know if they changed spawns now).
Pools: You used to be able to run to queen aggroing several charged groups, kill queen then dcharge over the heads of the charged to get away (charged aggro = sliver fuel). I don't know how many skeles spawn there now, but with an E/A maybe this is still possible before you die?
Mnts: nothing to say really other than an E/A should have a consistent 6min without too much trouble.
Wastes: Pre-nerf I used to do this in two pulls using a speed boost, which I guess you have to do now anyway because of the skele where king spawns.
Chamber: Take wastrel's worry end of
Also you really do not need more than 3 points in inspiration, with grail channeling lasts 21secs and if you use eggs+corn as well then it's even longer.
A/D: lower the points in shadow arts so you can increase crit strikes and/or scythe. 10/10/11 split with 11 in crit works well if you use corn+eggs, otherwise 11 in shadow.
Using a Me/A with aneurysm will do crazy damage to terras if that would be useful anywhere (wasn't pre-nerf but who knows).
Also have a quick look at this, see if some of those ideas might work.