What's interesting to me is new board games aren't just variants on existing games; there's noticable innovation in board game "technology". If you ever play board games from the 80s and 90s, they often feel dated and clunky, even more so than video games from the same era.

I recently went back and played some classic Avalon Hill games that were popular when I was a kid. I can't believe me and my friends spent so much time playing them when we were younger. Depending on the game, a full game might take 5 or 10 hours. For many games, the majority of the time is spent rolling dice, looking things up in tables, and moving stacks of counters around. And that's when you're lucky enough to have a chance to do anything -- there's often half an hour or more of dead time when you're waiting for other players to make their moves. By contrast, if you play a game of Dominion, it's possible to finish a game in 15 minutes. You'll have to make a larger number of important tactical and strategic decisions than you would in most six hour long games from the 80s and there's zero idle time [1].

Even with games that use modern game technology, you can see a noticeable improvement over time. Puerto Rico introduced a move selection system that allowed for serious tactical planning (10+ moves ahead) in a lightweight [2] game that could be finished in half an hour (with experienced players). But, the game wasn't perfect. One weakness was that the player turn order was fixed and very important. If you play a game with one weak player and three strong players, whoever goes after the weak player is almost guaranteed to win. Conversely, if you have one strong player, whoever sits down to the left of that player is going to get crushed.

Caylus fixed that by building a mechanism to change turn order into the game itself. Caylus was wildly popular for a year or two, but it's rare to see people play it now. Ironically, the game designer was too good at removing the element of luck for the game to be popular. If you ever played on BSW (an online board game service), you probably ran into 'Alexfrog', who had a record of something like 431 wins and 2 losses. You can predict, with very high probability, the outcome of the game based solely on who's playing, and most people don't like being crushed by the same players over and over again. Another issue the game had was that the gameplay was almost purely tactical. There were only a few viable strategies, so games all had a similar feel to them.

Agricola and Dominion fixed the problems Caylus had by adding significant randomization. Not only does that add strategic variety to the games [2], it also means that anyone can win any given game.

It would be fun to sit down and draw out a board game tech tree. It might hard to make a decent visualization, though, because of the huge span, plus a high degree of multiple inheritance.

[1] There may be some idle time with certain strategies on some of the newer expansions, due to the incredible amount of shuffling required. You can avoid this by playing here: http://dominion.isotropic.org/. I tend to play on isotropic even when playing face-to-face games because it's 2x faster normally, and there are some pathological cases where it's over an order of magnitude faster.

[2] I'm using 'light' to refer to how cumbersome and complex the game mechanics are. Examples of 'heavy' games are Enemy at the Gates (which has over 1000 counters) and ASL (which has something like 500 pages of rules).

[3] Both games do this by strongly randomizing the initial state of the game, and adding a small degree of randomization throughout the game. Technically, Caylus also randomized the initial state, but the initial random state in Caylus was minor; it was just barely enough keep you from pre-computing an opening book, the way you can in chess. Even in Dominion tournament games, where most players have played thousands of games, it's common to see wildly divergent strategies, because neither player has played on a board with a similar starting state, so they both have to figure out the best strategy in real time. I always cringe when that happens, and I realize I'm playing an inferior strategy. It doesn't really help that you can see what they other player is doing, because if you realize that her strategy is superior and try to switch, you'll be doing the same thing, but N turns behind, which is pretty much a guaranteed loss [4]. Your only hope, at that point, is some combination of superior tactical play and luck.

[4] Well, not always. A hybrid strategy can work in some cases. It depends on the strategies and the stage of the game. It depends is a safe answer to pretty much any strategy question, which is what makes it interesting.