Oh, one thing I forgot to add that I would be extremely greatful for: the path tracer is an amazing tool, and the denoiser vastly increases the image quality on lower ( ~400 SPP) sample counts, but the denoiser tends to knock out a lot of fine-surface detail and normal information. For example, when testing out the Realistic Rendering scene, the denoiser removed most of the high-frequency detail in the plaster and the leather, leading to an almost plastic-y look that didn’t match the real-time scene.
If possible, I would love it if the path tracer had the option to introduce textures (including normal) after the diffuse lighting has already been denoised (Quake 2 RTX and other real-time path tracers did this). I know they used Lambertian BRDF for diffuse and cut other corners for speed over physical accuracy, but I would personally prefer a more accurate but physically imperfect ground truth over having to wait for 10,000+ SPPS to converge.
Also, and I know this is a big ask and almost certainly not a 5.1 thing, but some sort of GPU-based denoiser similar to A-SVGF or ReBlur (might be proprietary though). NVRTX didn’t feature any support for real-time path tracing, despite the fact that there are code and denoisers that could be used for it, powering other systems like RTXDI. Moreover, my main issue with the OpenImage (CPU) denoiser is that it causes my computer to hitch massively whenever it runs, which can be a little frustrating during quick iteration. Still, very good for final shots.