Why Do People Design Variants?
It is natural, I suppose, that people will adapt their surroundings to suit their own particular fancies or needs. There is nothing sacrosanct about rules for board games, even Chess has a whole host of variants, many played by very experienced players for relaxation. And so with Diplomacy. The basic movement and combat system used in Diplomacy is essentially very simple and well suited to other scenarios. Indeed although the actual scenario used by Allan Calhamer when he put the game together in the 50's is what creates an inherently imbalanced (and therefore more interesting) game, it is perhaps the least important element.
Many Diplomacy players have tried to explore the concept of a game of Diplomacy game beyond the confines of the boxed article for all sorts of reasons; perhaps the player is bored with Europe in 1900 and wants a new scenario, perhaps he doesn't think that the regular game is realistic enough, perhaps it is the by-product of a handy pencil and paper and a fertile imagination, or maybe a group of regular players finds seven an awkward number and would prefer a game for 5, 6, 8, 9 or 10. Indeed, the very first variant of all, Youngstown, was invented because the Youngstown Diplomacy Club had ten members, so Rod Walker extended the board to add China, Japan and India to the original seven Powers - that way everyone got a game. Youngstown VIIB was eventually used by Doug Wakefield as a basis for Mercator, the 17 player variant which is still popular despite its comparative complexity.
Diplomacy variants come in all shapes and sizes. Although I cannot claim that this definition is exhaustive, essentially a Diplomacy variant is a game which takes an element of regular Diplomacy (the combat system, the movement system, the scenario) and then adapts that element to create a different game. Many variants are really variants of variants. There is a convention whereby if someone revises his or her own variant or a variant designed by someone else, then a version number will appear after the name of that particular version. For example, Lew Pulsipher invented Conquest of the New World in 1979. In 1980 Fred Davis revised it and called it Conquest of the New World II. Conquest of the New World III was a second Fred Davis revision dating from 1983. All games evolve; it is amusing to note that the original Diplomacy rules as devised by the game's inventor are now available from the UK Variant Bank as a variant!
Some designers take the regular rules more or less wholesale add a couple of new rules, and change the board lay-out (E.g. Zeus IV, Game of the Clans II, Excalibur, Discovery of the New World III). These "map variants" are usually historical or fantasy based, though they can end up looking like very different games indeed (take a look at London Nights which is about civil disorder in London). Other variants seek to retain the basic Diplomacy scenario and expand it in some way, through the use of additional rules (E.g. Multiplicity II or Vain Star) and/or minor map changes (E.g. Pride of Armies). Some variants do not even change the game at all, they only seek to limit the information available to the players (E.g. Stab!). Two player variants (such as English Civil War IIa) by definition have no element of diplomacy in them at all and merely seek to use the rule mechanics to create a strategy game. Other “variants” such as Bourse and Troubleshooter, are really completely different games in their own right, played alongside a totally regular game of Diplomacy (and as such may not be variants at all).
And Why Do People Play Them?
The attraction of playing a variant depends to an extent on the sort of variant you are playing. Some people just want to find out what difference it would make to a game of Diplomacy if Italy started the game with F(Rom) instead of A(Rom). Even a minor change like that can make a significant impact on the game. Why stop there? What would happen if Venice and Trieste were not adjacent? Maybe all seven Powers should be allowed to change their opening positions. At the end of the day, if you have played Turkey three or four times you are going to run out of inspiration.
If you like, say, Tolkien, why not play Diplomacy in a Lord of the Rings setting. If ancient history is your particular interest, wouldn't it be nice to lead Carthaginian elephants against Rome for a change. To an extent, map change variants are relatively simple games, although they may offer different strategy permutations from the original game, they are probably not going to be as good (if only because Diplomacy is well play-tested after all these years). But despite the cynics, scenario does matter. It does matter that a space on the board is called, Minas Tirith, or Burgundy, or New York or Jupiter, because the setting of the game is what helps to involve the players, to capture their enthusiasm, over and above the strategy.
Most variants are played for fun. There is a certain amount of kudos available for winning a game of Mercator (after all it shows you were intelligent enough to understand the rules), but don't expect to make your reputation for being a dab hand at casting spells in Vain Rats.
One real disadvantage in playing a variant is that it does require a degree of effort over and above that required to play regular Diplomacy. There is no glossy board to be pulled out when you want to write your orders. If you want anything over and above a photocopy of a map, you will have to make it yourself. Variants with more than seven players can be a real bummer if you only have seven different colours to choose from when using the pieces in your Diplomacy set. Even the mental effort involved in examining the options available to you when writing orders for a variant should not be overlooked - most variant players are very familiar with the regular game, but whether or not Inveray borders Blair in Game of the Clans is not immediately apparent. You may have to get a board out and set a game up just to be able to understand the letters you get!
I believe that the effort is worth it, provided you are the sort of person who wants to make the most of it. Don't play a variant half-heartedly. You won't enjoy it, you will lose and you will make the game less enjoyable for others. But if you really want to try, don't hesitate. It's fun.