You have to wonder if it is really needed (the collar). This lens is only 20 grams (.7oz) heavier than the new 18-300mm which has no way to attach a collar.
I've done a comparison of the 180mm f/2.8 using the camera's tripod mount and a Manfrotto lens support. Under windy conditions, the lens support was a clear winner, but that could have been due to the added mass of the support. With a "tap" test on my old metal Manfrotto tripod, the lens support also decreased settle times.
So my guess is that adding the tripod mount will make it a bit easier to get the most out of this lens.
One of the biggest mistakes a photographer can make is to look at the real world and cling to the vain hope that next time his film will somehow bear a closer resemblance to it. - Galen Rowell