Yeah the stock old ntpd had a lot of unused code and various security problems over the years. It makes sense OpenBSD would replace it. Just a shame they didn't do it completely. I think that describes a lot of OpenBSD tools; you're trading off some functionality for very good security.

There are better NTP implementations now. Chrony is great, it's the default in Ubuntu now. NTPsec is coming along although I haven't tried to use it myself. Also good ol' ntpd is greatly improved.

https://chrony.tuxfamily.org/ https://www.ntpsec.org/