I think I side with most board gamers when saying that the mechanics and the theme are the two most important parts of any board game. That being said, why are there still good great games that still have such poor graphic design and/or illustration? The game I'm going to talk about, in particular, is Terraforming Mars.
Terraforming Mars is a great game and has some awesome mechanics! I own it for that reason, but the graphic design and illustration is not up to speed. Just to be clear, I'm not talking about the quality of materials, I understand why they're lower quality than they could be; in order to maintain a lower price point for the game. My issue is with the aesthetic design of this game. Below you'll find some images that demonstrate this:
There are so many boring, flat, and just very unflattering graphical elements in this game that I could talk about, but this blog post shouldn't be a book. Just to reiterate: this game is awesome, which is why I want every facet of its design to be as good of quality as its mechanics (Scythe is a great example of making every aspect high quality).
We need to talk about this in board games more often. I feel that once people love the play style of a game, they all look over the art with "rose-colored glasses". These huge companies, cranking out all these "evergreen" games, should be held to a higher artistic standard.