Actually, it even seems odd to use the word traditional when discussing a hobby that's a little over a half-century old, but most people will understand what I mean -- traditional being the hex-and-counter wargames inaugurated by Charles Roberts/Avalon Hill and made ubiquitous by James Dunnigan/SPI in the 1960s/70s/80s.
For many people hex-and-counter wargames are wargames and they pay little mind to other design choices or even disdain them.
On the other hand, there have always been other ways to skin that particular design cat. Many wargames from the hex-and-counter designers didn't use hexes at all, of course. Area movement and point-to-point maps have a long history in the hobby. And there have always been some games that were outside the main wargame design tradition, such as Kingmaker, Diplomacy, block wargames like Quebec 1759, Axis & Allies and the whole traditional miniatures line.
But for a long time hex-and-counter wargames were definitely where the action was design-wise. This provided many benefits, because the sharing of mechanics and design techniques within a limited universe of choices made it possible for wargamers to digest literally hundreds of wargames in a short period of time. A big draw for series games such as The Great Battles of the American Civil War, the various SPI quad games, The Gamers' various series (SCS,OCS,TCS,NBS etc.) etc. was that it allowed players to concentrate on the battle at hand instead of having to learn brand new game systems all the time.
On the other hand, this self-policing limitation on design tools did have some drawbacks. One of them is that not all situations lent themselves equally well to hex-and-counter wargames. Hexes have geometric limitations that made them problematic for linear warfare and tactical warfare at sea. Counters, being two-sided, imposed limits on fog of war or step reduction unless you added more counters to the pile. Zones of control, combat results tables and well-defined scales often brought anomalies or awkward compromises when applied to specific situations. And as time went on it seems as though hex-and-counter wargames had trouble recruiting new players, while the euro-style games attracted more interest.
Now, like any generalities, these kinds of statements obscure a host of counter examples. Hex-and-counter game manufacturers have gotten pretty adept at marketing their wares to the sort of p,layers who will find them interesting and the Internet has been a great aid. Players can find each other and game makers easily. Many hex-and-counter wargames have turned out to be well-suited for online play, so it's not all doom and gloom.
But at the same time, I am sensing a renewed interest in other design approaches. One very popular line of attack has been what are commonly called card-driven games, which use the detail and flexibility that cards can provide to bypass the chart-heavy approach of traditional wargame designs. Still, most of these designs are coming from h&c game companies and designers and still share many of their attributes, such as cardboard counters and even hexes.
There's a lot more interest in alternative design approaches. While both Axis & Allies and block wargames have been around for decades, both are showing new life these days.
And some designers have explored some completely different approaches to wargame design. Some notable recent examples include Friedrich, Bonaparte at Marengo and Napoleon's Triumph. And I put Martin Wallace's Waterloo in that category. Despite having little in common with a traditional hex-and-counter treatment of Waterloo, the game does good job of capturing the essential features of Napoleonic era combat and I think it's an instructive, as well as entertaining exercise, which is what a good wargame ought to be.
What will be interesting is seeing how Wallace and Bowen Simmons (designer of Bonaparte at Marengo and Napoleon's Triumph) come up with next. Both designers are reportedly working on a Gettysburg game, and both games are likely to appear in 2010. Back in the heyday of AH and SPI it wasn't uncommon to see both companies releasing competing visions of the same topic, so it's nice to see that sort of choice being offered again. The more the merrier.