Is the change from 3 (technically there should be 4 for servers) to only 1 intentional?

(Note that I noticed that recent ntp versions is not working very well with pool configuration, but didn't get a chance to trace that down yet).

It's not a change to 1 server -- because of the "tos minclock 3 maxclock 6" line, ntpd will automatically add 5 servers from freebsd.pool.ntp.org, then if those 5 don't give at least 3 that are providing good time, it will add even more (and eventually drop off the ones that provide lower-quality time). Maybe I should move the "tos" line and its comment to be above the pool statement, so that the comment about automatically getting 3-5 servers is sort of already in scope in your mind when you read the pool comments.

To avoid a lot of traffic at startup, ntpd adds servers from the pool in groups of 4, so when it first starts it adds 4 servers and does iburst (8-packet) exchanges with them. After 4 polling cycles (4 minutes, basically), it will add another group of 4 (or as many more needed to reach the goal of at least 3 good out of 5 total).

I agree that 4 is a good minimum number of servers. I like 5 a wee bit better because of ntpd's majority rule on leap seconds -- it requires more than half, and the comparison in the code is >, not >=, so 3 out of 4 servers would have to be signaling a leap second to be believed. Having an odd number gives an automatic tie-breaker.