Last question first. Exactly, especially with the visual textures of suburbia in which to camoflage an aeroplane. The only problem I see with making it an MBZ is that some of the a/c using it (OK, it was me who picked the ultralight scenario, yet not to pick on them mind you), is that the very fact that they do not possess a radion within some of their a/c is enough to exclude them (the ones with no radios), from using the lane. SY radar obviously does a magnificent job, as in the past I have also recieved traffic advisories from him/her. I honestly feel that the "pointy end" of RIC CTR is a waste of airspace as it is not often frequented by MIL a/c. I would suggest shaving at least another 3-5 nm OFF of it to perhaps give the a/c flying from other places (ie; HOX, CN etc) a bit more space to manouvre in without the current situation of funnelling and bottleneck.
A CTAF is from what I can see the best alternative and that way one can draw a better situational awareness picture without having to listen to all of those seaplanes that Mr Smith seems to have a problem with......
SY radar to stay, though...... He's worth his wieght in gold!