Hi, this is an interesting debate, and as a private pilote, I will give my opinion :
With Reshade, X-plane 11 looks beautiful.
Without Reshade, X-plane 11 default looks more realistic.
Very often, on a sunny day, even with a nice blue sky, the visibility is quite poor. Especially when facing the sun.
It's actually very rare to have a clear sky with a visibility of more than 30 kilometers.
Moreover, the ground looks most of the time like a grey and dark mass.
It is important to keep one thing in mind. When we see an aerial picture, it's been taken in the best conditions, at low altitude, and very often the contrast and the colours have been improved afterwards.