I agree with you - I'd love to see all the camera manufacturers implement better internal codecs. and by better, I mean:
Scalable compressed internal RAW (best)
Prores internal
Scalable uncompressed internal RAW
Unscalable uncompressed internal RAW
High-bitrate low-processed high-quality h264/5
High-bitrate low-processed typical-quality h264/5
Whatever h264/5 implementation the marketing department thought was good
What I mean by "scalable" RAW is the ability to read the whole sensor, downscale in-camera, and write that in a RAW format to the card. I believe the P6K can do this? It's how you can get different resolution RAW files with the same crop factor.
Unfortunately, most cameras are "7" on the above scale, with only a few exceptions here and there, and those are often very compromised in other ways. Effectively, an external Prores recorder upgrades all the "7" cameras into "2" cameras.
Cameras are always a compromise, some have this function but not that function, others are the other way around, etc. I'm looking to eliminate one of those variables.