I agree that other things being equal, it's much easier to bushwhack down a steep pitch than uphill.
I led this route as an AMC trip in Sept. 2010. At that time, the spruce was fairly intense (~7 on a scale of 1 to 10) coming off of the Carrigain summit, along with some similarly difficult, steep stick forest approaching and then heading down off of the NE Carrigain summit. Navigation (with the exception of having to wander the relatively large/flat Vose summit looking for the canister) was not a challenge, due principally to the fact that our route was almost always to follow the spine of a ridge -- Carrigain's NE ridge, then Vose's SE ridge until we made a final turn to intercept the Carrigain Notch Trail. Along the route, we encountered interesting slides coming off NE Carrigain into the Vose col, as well as on our route down from Vose.
The group really enjoyed this bold variety of bushwhacking features: spruce, stick forest, slides, herd path, ridge terrain, steep woods -- and coincidentally, it was also a splendid day for ascending Signal Ridge and enjoying the views from the Carrigain summit. From the rock slide below Vose, we were also treated to some a dramatic view of the fortress-like face of Signal Ridge that we had traversed just hours prior.
Though only 11-miles on paper, it was epic. The group summited Carrigain in 3.5 hours, then took 3 hrs to reach Vose, 2:15 to get down to Carrigain Notch, then another 1:20 to complete the hike. Counting view breaks, it was an 11-hour day. I chuckled to myself at how nearly textbook the bushwhacking times turned out to be -- 0.5mph is a good rule of thumb to use in planning unless you know of specific, really hard obstacles -- but you don't expect your actuals to hit that dead-on.
So anyway, my recommendations would be twofold. First, it's a big day, so do yourself the favor of starting as early in the morning as possible in order to allow yourself maximum contingency time on the back end ahead of sunset. And second, don't do this if there's rain in the forecast -- wait for a clear day.
Alex