I don't think Enterprise will look that good on Blu-ray. The CGI didn't age very well. The live action footage isn't great either.
I found some screenshots for the second season episode "Minefield". Source is the 1080p iTunes download.
thanks for the screencaps in HD from the low bit rate iTunes download.
I think ENT will look as good as it can for consumers on Blu-ray with the highest bit-rate available in HD to any Trek fan.
I really liked season 3 and plan on purchasing it on Blu-ray.
With season 4 being the first Trek TV series to be shot digitally with HD cameras and it was during the HD infancy of television shooting narrative dramas in the US on HD cameras I think it will have the limitations of the available Sony F-900 HDCAM cameras at the time: 8-bit recording with interpolated 3:1:1 color sampling and the resolution up-converted in-camera from a 1440x1080 sensor which was 1990s HD camera technology.
Even though the show was mastered most likely to 10-bit D-5 HD tape season 4 would have the lowest quality overall due to the source not being 35mm film.
I think seasons 1 & 2 I can live with on DVD only.
Surely the next Trek TV series will be shot with a a state-of-the-art 4k digital cinema camera
using RAW data or a high bit rate and sampling level codec.