roulette:
C/ I'd suggest the "air carrier Baro based Cat II, in the 707 DC8 era" were done with very well trained pilots in an organisation which had an appreciation of risk that was very different from that which would be regarded as acceptable for RPT and even freight dog operators.
My airline (the late TWA) first got approval for CAT II in the 707 with baro alone. It didn't work out very well. So, they added radar altimeters to the entire 707 fleet.
My view was (and is) that CAT II in the 707 era was a dicey proposition. The later fail-operational auto-land birds made CAT II safe (L1011 and 757/767 in our case).
As to the VEB, we get a lot more out of Baro VNAV than with LNAV/VNAV. I think we've hit the stops on that one.
LNAV/VNAV, as an SBAS level of service, is far better than the Baro VEB.
LPV is better yet. An RNP AR FMS suite that would switch from RNP AR/VEB to LPV the last 1.5 miles, or so, would yield far better results than even RNP 0.10 with VEB Baro.
The GQS is not going away, though, for any approach with vertical guidance (excluding advisory vertical guidance, which is sorely misunderstood by many operators and
may have been a factor in the KBHM accident).