Of course I agree, however comparing the risk of those few packages (that don't even change the system much, it's more of a monitoring thing) to the whole virtualization we can say that if someone came that far he knows what he's doing. Alternately you could continue creating your own build that does include those packages, although I don't think it's less risky.Just a word of warning that you are in unsupported territory by trying to install packages yourself. We've warned God and Country about not doing package installs this way, so do this at your own peril.
Besides that if you try to install a wrong package some cases will be handled by the package manager:
pkg: wrong architecture: FreeBSD:9:amd64 instead of FreeBSD:10:amd64
By the way I had to change the following tunable when switching from 9.3 to 9.10 so that my passthrough devices show up properly:
The background is explained here:
Apart from that I removed / disabled the following three variables:
So from many tweaks in the past it actually comes down to one single tunable thanks to FreeBSD10.