Have you tried calibrating your monitor? It starts to sound like at least part of the issue might be on your hardware or hardware settings.
I still prefer the original picture on your link. The colour balance seems to be more pleasant to my eyes.
The supposedly improved one is just over saturated/burned and the colour balance is too much on the yellow side to me. I think it’s gone a bit overboard on the balance when trying to add warmness on the picture. If one wants it more brighter, the added brightness should be targeted only on darker or mid tones/colours to avoid the burning/overexposure or whatever it’s called in English. I mean that some brighter areas lose too much details and look almost undetailed white blotches in the middle of really bright areas. The same areas are on the original pic too but they don’t look as distinctive and obtrusive to me.
There’s probably no point trying to make cropped screenshots from those pics and explain what I meant if the problem actually lies on different monitors and their calibrations. And your point probably wasn’t that the game should be exactly like on that altered screenshot either because that software seems to lose details (especially near the bright areas) through processing.
Anyways, what I wanted to say that while the colour theme is pastel everything, it’s not dull, depressing, and everything being either a blue, grey or some form of brown for me. Unless you were greatly exaggerating, then you might want to check your monitor and/or graphics card settings.