We’re still barely moved away from baked lighting and reflections (and all the limitations that entails), and all of the current solutions for dynamic GI and reflections run like crap while still being noisy as hell. We need a hell of a lot more compute to actually run full quality on both of those without all the noise and shimmering we see in current titles.
Transparency in general is still extremely awful. Deferred renderers fundamentally can’t handle transparency- a G buffer can only store a single object per pixel, which means as soon as you have a translucent piece of glass in front of a solid object, you start having to use hacks and workarounds. And God forbid you might actually want multiple translucent things layered in front of one another, and expect them to render consistently.
There’s just a lot of things that we have bad hacks to work around right now, that would be solved when we move to proper path tracing with sufficient compute power to make it shine.