Hi Tommy,
Sorry for your frustration, you deserve a more detailed explanation that what we provided initially. The reason we decided not integrate this pull request is because we have plans to modify that area significantly to make it more performant. Your pull request is indeed correct and adds funcionality that surely users will find welcome. In fact, your implementation is familiar to us: we do pretty much the same in the reference path tracer (pathtracing.ush) for dealing with emissive geometry.
That technique is suitable for interactive rendering but slow for real time, where ray budgets are very low. In fact as you saw yourself you need to increase the amount of samples a lot, cranking it up to 30spp or more to get good results in simple scenes. We have plans to improve our light sampling techniques in the 4.24-4.25 time frame and these improvement will bring this funtionality together with other enhancements. We prefer not to integrate pull request that could collide with the changes we are already working on this particular area. Of course, you all are very welcome to integrate this pull request into your code base in the meantime.
Again, thanks so much for your pull request and sorry for not giving you a more detailed answer before.
Regards,
Juan