As someone who both ran a RPG line and, a few years later, a comic book series, I would have refused the second illustration strictly because the art is bad.
Out of curiosity, what would you say makes the second picture "bad" and the first "good" (or at least acceptable)? I ask from the perspective of someone who knows nothing about art theory, and sees only two pictures both done with a technical competence I certainly couldn't deliver myself.
I am certainly not a fan of the style of the second painting vs. the first, but a difference in taste is not the same as a criticism of quality, I think.
Just want to comment that the first picture is from Everquest, where you can play a dark elf or a catman or a lizard man. Positivley "New School" gaming there.
The first one is by the late Keith Parkinson, one of the "big four" of D&D and esp. "Dragonlance" (along with Elmore, Easley and Caldwell).
The first thing you notice about the second one is how the composition is all wrong. Not only it is unbalanced, but important elements are muddled. The little lizardman in the middle disappears amid all the other elements surrounding him. The two figure fighting in the lower right partially obscure the two other figures behind them (Parkinson apparently does the same, but it his version the way the figures are placed doesn't hide the ones in the background).
Generally speaking, Parkinson's illustration gives more "air" to the scene, allowing to each figure to be properly perceived. His dragon isn't big and it hadn't to be. The "bigger is better" dragon in the second illustration only results in an orange blob in a scene already crammed.
Parkinson uses colors to further detach each character both from the ambience and from each other (you could say that the paladin in white against the white boulders is his only mistake). The second image is a "garish is better" assault on the retinas.
Then the characters. Parkinson's show an elegance and beauty that - as a side effect - makes the player say "I want to play this one!". They are also anatomically correct. Now, tell me why I should want to play the befuddled ranger (?) on the left (after I realised that she was an archer only after staring to her for a while, because her bow almost belongs to a game of "hidden objects"). Who is fighting with who is often unclear. I have a few doubts about the anatomies. And, for all the attempt to show "superheroic characters" in the second image, Parkinson's poses are cooler.
These are the first things that come off my head. Generally speaking, Parkinson's work shows a guy who has mastered his talent and knows to convey the spirit of what he is illustrating in the best possible way. The second image is done by someone who apes better artists, but who still has to understand that cramming everything together and failing at the basic use of colors only shows how he still has a long road in front of him.