I tempered with TAA code and managed to make it sharp at the cost of some aliasing. Artefacts (overall blurriness, smearing, ghosting) are reduced, temporal stability kind of looks like with 8xMSAA and specular aliasing is still taken care of. (And all this by only changing one number in code.)
…(installation path)/Epic Games/4.14/Engine/Shaders/PostProcessTemporalCommon.usf
under the ‘COMPUTE BLEND AMOUNT’ section I changed “BlendFinal = 0.04” to “BlendFinal = 0.25”
and run the console command “r.TemporalAASamples 2”
Moving foliage looks a lot better this way and everything is sharper.
What I still can’t find out is how to change the number of frames TAA blends together.