Improved Features:
1. IN CAMERA PROXIES... no one talks about this on youtube!!
2. dual card recording ability, dual writing ability
3. HLG color space, no overheating
4. Bright and Beautiful monitor, focus peaking, customizable buttons, uncompressed RAW photo capability, a large buffer depending on card size, and great autofocus with eye AF and face tracking... plus better "color science." Color science means absolutely nothing unless you are delivering a final image or video straight out of the camera, its all subjective and if you want Accurate colors Sony is the way to go. I could rant for pages about "color science."
5. Headphone Jack... Monitoring external audio is absolutely important if you are running wireless mics. I will use this to monitor my wedding ceremony Audio.
Things that could be improved:
1. The EVF is not calibrated color wise to match the display screen on the back of the camera... not a huge deal for video but it can get annoying for photo. Know your settings well enough to get you close in photos, and the RAW capabilities in Lightroom will give you some leeway.
2. No face tracking while using an external recorder AND recording in Camera. If you record solely on the external recorder you can still retain face tracking which is not a huge deal, there is an option in the settings but it turns the external screen black.
3. only 1 UHS-II slot. I would love to see two of them.
4. no 10-bit color depth... this is probably coming on the a7siii which I understand, but it would be incredible to get a firmware update on the a7iii, a7riii, and a9 to allow 10-bit color, making SLOG and HLG way easier to expose for and work with in post. Also, it allows creators to keep their a7iii and purchase an a7siii to match perfectly with it.
5. The shutter button is a little spongy... not a huge complaint here because I am being rather critical
The a7iii has improved almost all of the issues thus far I have experienced with Sony APS-C Cameras. In my example photos and videos, I used the 70-200 f/2.8 GM (incredible lens). The a7iii lasted 4.5 hours of continuous video and photo shooting to two different SD cards with a completely bright viewfinder and screen with 20% battery to spare... something I could only dream of on the 6300. This is absolutely a professional camera and is reasonably priced for the features it has.
if you are looking for a prosumer camera with pro features... you can't go wrong with the a7iii. It definitely is not a cinema camera but will absolutely serve me well until I need to upgrade in the future for both photo and video.