The extremes of this is 18XX: there are plenty of games within this genre that aren't just unprofessional, but downright ugly, cluttered and obviously designed by the creator of the game rather than a professional graphic designer. This is especially apparent in 1860, since the game map is, quite bluntly, a mess. Even then, I have played and enjoyed 1860.
This article, however, is not about me, but the general feelings that most other boardgamers have and even some of my own biases against certain graphical/production designs. What this article will not examine, however, is the so-often mentioned divide of boardgames into strictly euro/american designs, a distinction which I find is nowadays evaporating so rapidly that the distinction, even if they were valid once upon a time, is essentially gone nowadays.
Design is important in a number of ways, but it is important to first outline that, much like enjoyment/fun, graphical design does have an element of subjectivity to it: what someone might find appealing might be entirely unappealing to someone else (something which I will showcase later by examining my own biases). This is not to say that the graphical design of a boardgame cannot be evaluated from an objective basis, however.
As I'm not a graphics designer I won't outline every single possible sin that is possible to commit, but some of the foremost ones would be things like including too much writing on the board: 1860 is pretty guilty of this, with the entire board circled by rules explanation boxes. Writing on a board should, I feel, be restricted to simply labeling rather than explaining.
As an example, look at the aforementioned 1860 board below:
Although better than other 18XX boards I've seen, it looks seriously cluttered in terms of writing. If you need to explain something without having the player reference the rules, I always feel that a game is better served by cheat-sheets, something that GMT has obviously taken to heart.
I have to admit that there have been too many times to count when someone approached a table when I was playing an 18XX game and said 'man this game looks hard'. Maybe that can be attributed to the nature of the genre, but a part of it is also the graphical design. As much maligned as the graphical redesign of the new(ish) version of 1830 was, it does look more inviting to a potential new player, which strikes at one of the issues that I think is most important when discussing design: accessibility.
The first contact that a new player makes with a game is the design of it: they look at the components, analyse the board and are immediately given an impression of what the game is and the general feel of it. If they see a bunch of wooden cubes on the board, they are going to be given a different perception than if they see sculpted plastic miniatures. Their initial assumptions about the game might be incorrect, but that first impression is a powerful motivator for wanting to play the game (or not).
It's why it can be important to be immediately visually striking: an awesome example of this is Cash 'n' Guns: if you watch a game of it from the distance you are immediately struck by the sight of people pointing foam guns at each other: it's the sort of thing that makes an immediate impact.
Another important factor is theme. Design of a boardgame can directly supplement the theme or not, something that I personally find weird but that seems to influence a lot of people. The prime example is Lords of Waterdeep: does the mere design decision of turning the cubes into meeples enhance the theme of the game? When you are handling cubes, they might be any resource. When they are meeple, you feel like you are allotting people to quests substantially more.
Tash-Kalar was also something that seems to have a similar issue. People don't feel like it is thematic because not only does it feel like an abstract game, but also because it's DESIGNED as an abstract game. See the picture below if you are unfamiliar with the game:
The cardboard chits are highly reminiscent of other grid-based abstract games. What if all the components were replaced by plastic crystals, as stated in the lore? Would the game immediately become more thematic because of it, even though the mechanisms of the game have not changed one bit? In the past I would have said no, but that almost seems to deny the importance of design within the context of boardgames.
A perfect example of the importance of design is the game Automobile by Martin Wallace. Automobile was originally designed and produced by Tree Frog Games usually their usual toned-down aesthetics, with the following graphics used:
The design is not exactly pretty, but very utilitarian and easy to follow once you know the game. Notice for a start the distinctive difference between the three different types of cars, with dark blue, brass and light blue that can be easily distinguished. Automobile was republished by Mayfair, leading to this design:
To me, the redesign is less clean than the original printing, even though the graphics have certainly improved. Most of the changes feel overly elaborated and actually can be detrimental: for example, there are two 'turn-tracks' in the game which in the original design are next to each other, while in the redesign they are placed away from each other, meaning that it is not possible to slide the tokens from one track to the other.
The main sin of the redesign in my eyes is, however, that all of the wooden pieces in the original design are now substituted with cardboard chits. I must admit that I love my wooden pieces: it was a joy for me to get Martin Wallace's Gettysburg and Waterloo, since they contained so many lovely wooden pieces.
Apart from my bias, using counters instead of wooden pieces actually detracts from the redesign: it is much easier to count the number of wooden car tokens present in a space rather than picking up the cardboard counters in order to count them.
Another game in which this bias of mine came to the surface was regarding BattleCry, the American Civil War game that inspired Command & Colours and Memoir '44. I would buy BattleCry in an heartbeat if it wasn't for the ugly (to me) plastic soldiers present in the 150th anniversary edition. To me, the visual design of Command & Colours and its wooden blocks is much more appealing than plastic components, although I am aware that this is a bias unique to me.
To end this long, rambling article, I feel that many there are sections of boardgamers (euro-gamers in particular) which like to sacrifice good design at the altar of 'good rules' or 'good gameplay'. To me, it is becoming apparent that this shouldn't be the case and many of the games that I regularly enjoy playing have stellar, vibrant designs coupled with good rules (a premier example is Dungeon Lords/Petz, games which I've seen attract people just due to their design alone). The future of boardgaming is in the hands of hybrid games: designs that manage to excel in all categories and are not needlessly restricted.
