If you look at the way YC demo day works, its a pretty reasonable way for potential investors to find startups which are compatible with their investment goals. I think this addresses the challenge of the general solicitation rule (finding the startups) without the negative of creating a bunch of unvetted startups advertising for dollars. Basically, I believe lifting this ban increases the noise significantly without much boost to the signal.
The analog I thought about when I saw the SEC was thinking about going this way was the lift on advertising prescription drugs. That really hasn't been a 'win' for me, while I'm sure some folks have discovered there are drugs available their doctor didn't know about (signal), a whole lot more people are asking their doctors to give them drugs which aren't really appropriate to their symptoms (noise). It has made the national news shows practically infomercials for a variety of meds for 'old people problems'.