The issue is, the final effect as seen in P3D when using HDR keeps changing between each release so, we cannot keep changing the scenery to adjust to the new versions, and I'd say that, comparing to real world night time videos, your video is not that far off, and the big issue that always plagued FSX, is that runway lights were always far too weak.
The flicker is obviously entirely out of our control so, is that distracts you too much, you simply have to choose between using HDR or not.