I thought of it more as a means processing the CMP out signal upstream
of the LPF, for example, coming up with an alternative cmp strategy. I
suppose if the LPF is just a mini A-171, then one could just bypass
the entire LPF as you suggest and use the A-171 instead.

I am still mystified as to why the LPF output leads to smooth output
from the internal VCO, but causes jitter when going to an alternate
VCO. It's as though the internal VCO has a built in slew or something.