The way that the BSDs differentiate cannot be reduced in this way, not least because there is a lot of what Justin C. Sherrill (of the DragonFly Digest) calls 'cross-pollination' amongst the BSDs.
A case in point:
Superficially, and erroneously, one might observe that OpenBSD, NetBSD, and FreeBSD have nvi, and only DragonFlyBSD has nvi2. In fact there was a three-way fork of actual Bostic nvi, all of them making revisions and leaving the original behind, and then things got really complex with nvi2 taking from OpenBSD's nvi, and FreeBSD's nvi taking from nvi2; not even getting into the existence of nvi-m17n along the way and how there are nvis in base and nvis in ports. (https://news.ycombinator.com/item?id=48132452) One cannot divide the BSDs up into those that have nvi2 versus those that have nvi.
The split is complex in other areas, too.
You know even though I said the execution is unlike linux, in fact, there are many many details that are just like linux! What a freaking ignorant liar eh? There's like 100 things like that you could say. No wait, no way it's exactly 100. There's obviously some other number like 105 or 612 things like that. So superficial and wrong!
