The Game of Go is still pretty much the ultimate strategy game. No other game distills strategy to its essence, in such simplicity, and thus lets the complexity emerge.
The board is simplicity itself: a 19 X 19 Grid:
One aspect of Go is that you start from the corners, build a semi-secure formation, and then grow out from there.
For example, here is a recent game of mine in the early stages:
What if the board was a little different?
Chinese Checkers has 6 Points where people start:
What if we adapt this idea into a Go board?
Sometimes, less is more.
One interesting aspect of the Stratego board is that it has terrain features in the middle:
What if we cut out a some spaces in the middle of a go board, like this:
Or combine some of these ideas:
How would each of these variations modify the game? Many of the tactical patterns would stay the same, but would have a different role in the overall strategy.