I’m coming from the first generation watch and I feel the colors aren’t as vivid on the series 4. Also even with full brightness it doesn’t seem super bright. Just me? The colors look so much better setting up watchfaces on my X then the watch.
Did you move from an aluminum watch to a stainless steel one? The sapphire crystal on the stainless steel watch isn’t quite as clear as the glass on the aluminum watch and can mute the colors slightly. I don’t really find it noticeable in regular use, but if you compare two watches side by side you can see a difference.