Mike,
I expect that the reason for the lack of comments is that there are very few "tritonites" on the forum. I have the Workcentre and, whilst I found it quite useful, like you I wasn't happy with the dust extraction and your modification looks to be very useful in rectifying that. However, my main gripe with the Workcentre was the fact that you had to remove the riving knife from the saw and use the slot-in one supplied with the Workcentre. Mine never lined up properly with the saw blade despite trying to set it up according to the manual. It kept moving marginally away from the vertical if a hose was put into the top of the guard which meant that any wood over 1/2 inch thick would jam. The fact that the riving knife could only be vertical and so couldn't be used for an angled cut was also a pain. Eventually, I used mine just for cross cutting but have now bought a SCMS and use a circular saw with a guide rail for rip cuts thus rendering the Workcentre redundant.