It may not be just the mere presence of HD broadcasts on the same channel which is causing the additional noise in the analog FM signal. Most stations are probably using the same total power to radiate their signals as they once were. Some of that power is being siphoned off for HD broadcasting. Thus, the signal strength of the analog signal as picked up by the analog tuner will drop, resulting in more noise. Also, civilization just keeps adding to the noise heard in any given analog FM signal from any point on the map even if the signal strength at the transmitter remains the same. There is more and more interference from buildings and other RF transmissions. Pre-HD, I used to notice that my favorite classical station in Chicago, WFMT, got noisier and noisier as the years went by even though my home location did not change, constantly pushing me to upgrade tuners and antennas to retain a quiet signal.
The price of DaySequerra HD/FM tuners keeps dropping. The M4.2S, which replaces the M4.2r that I have, is said to be even better and now costs only $1,000 in its "basic" configuration. Mine cost close to $3,000 a few years back. See Radio Monitors > HD Radio Tuner > M4.2S at
http://www.daysequerra.com/ViewProduct.aspx
The squashed dynamics are just a product of what the station is doing, not HD Radio. The analog FM signal will sound just as squashed, if not more so, compared to the HD. Some stations at least lower their compression ratios via HD and internet streaming, compared to broadcast analog FM.
I agree that soundstage truncation is one of the minuses of HD Radio compared to analog FM as heard over an excellent analog tuner. The other downside is that the HD signal will usually sound brighter. But all other sonic aspects of HD are at least as good as analog FM if not better and usually, on balance, I prefer to listen to the HD signal from my home location.