It would be really nice if we could avoid degrading other people’s work, especially when it is 100 times more complicated than that, even for the “simple” recolors. They have to consider skin texture, scars on the body, precision lines for skin transition (like Goliath’s underbelly versus his leathery top layer), color fades, details such as spikes and eyes and claws, and not to mention this has to be done for each and every evolution stage of the monster. So please, consider the people behind the keyboard before you belittle hours of work without much of an idea of what you’re talking about.
I also feel I should mention that the people who work on the skins aren’t the ones who made the call that skins should initially be recolors. That is more of a top-down decision that considered many, many factors, the least of which is time-cost versus development deadlines and other such efficiencies.