Well, I’m not a big fan of using Tonemapper sharpen to solve ghosting issues. It introduces artifacting of its own.
Tweaking current frame weight based on world speed of the camera might seem situationally useful for certain games. You can also scale final blend by velocity data in the shader.
Problem with using reduced samples for TAA, is that at 4 samples, you are just using typical MSAA jitter offset pattern. It reduces TAA effectiveness to some degree as opposed to Halton sequence at 5 samples and above.
Improving TAA ,in my view, should be probably separated into two parts. The first part is coming up with better way of history clamping(I believe that I’ve read somewhere that orienting and stretching neightbour sampling pattern in direction of velocity helps, but haven’t tried it.).
The second part would be a better solution to calculating velocity offset based on depth difference. Right now the cross pattern with offset of 2 is used used by default. I’ve actually had some limited success with using a larger SNN filter for that, which blurs the borders of objects more, but results in less overall smearing of multiple layers of moving objects. This one in particular relates to foliage.