Well, it's not completely perfect, imo it's still a bunch of coding possibilities that Alex and CAS are trying to explore. It isn't a part of project reality, as Tirak has stated, but part of an add-on called combined arms.
What I do know is, with many of the headaches brought on with a few of the weapon systems (Radar especially, that's been a damned bugger

), even if the DEVs wanted to put it in pr, you'd need it perfected.
As Alex says, it's also about what you want to achieve in the mod to answer whether you want it in. If you don't/can't take a few things in the environment and make them realistic, what's the point of implementing realistic player/vehicle attributes? One of the thing combined arms has done is used maps with 2k view distances. I'm not sure how many of the systems would work in different settings, though, so you'd need to change many things of the mod to accompany it.
Not to say that it shouldn't be, but to say that it's a decision on whether/where/how to implement it.
ETA: for anyone confused about this, read the video's description before commenting:
upcoming Project Reality 0.85: "Combined Arms"
PROTIP!: THIS ISN'T ACTUALLY IN PR 0.85
