Yes, it's already in-game, and it is working for everyone (it's an engine thing, not a PR thing).
It isn't a very effective fix. Ironically, the OCC meshes are more effective in more built up areas, because basically you need one object to block the view of other objects (completely, even 1 pixel showing will render the other object), so on something like fallujah, there's quite a lot of space between buildings/roads, and thus unless you go right up to a building (where it takes most of your view and occludes other stuff), the performance improvement isn't that good. That's why I said the example above was a best-case scenario
It does make a little difference, especially since I did the enterable buildings as well, so you're not rendering players/weapons/caches inside buildings when you don't have direct LOS [line of sight] to them
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The biggest performance enhancers would be:
** Reducing the draw calls, having everything's final LOD just using one, basic color texture. Preferably higher LODs also reducing the texture call
* In addition to the point above, having more vegitation clusters rather than individual vegitation objects. The fields in fallujah, for example, rather than having a bunch of little ones, exporting the entire map's field areas as one object would help draw calls.
- Getting rid of the piecemeal afgan statics (It's like 20+ buildings merged into one)
- Like Rhino's guide for vehicles, having very low poly final LODS for everything
The problem with the above is that all of those steps are retrospective [not a good word choice, but can't find the right one] steps, and in many cases doing those kinds of changes can be very time consuming.