Imagine if you will, a typical 4x strategy game, where the players are represented as societies/races, and the principal motivating need is to propogate the species throughout the realm, and there is a competition among the players for territory.
An unsolved problem with this genre is that the current crop of games turn out to be an initial race, where whoever takes the early lead wins the game. The player who pulled ahead in the colony rush becomes far superior, and further combat is reduced to a mop-up operation. The race leader has no real threat of losing their territory, and taking all of the remaining realm is just a matter of time. New or young empires cannot thrive and win, because size is everything.
What can be done about it?
One possibility is that the model of empires as a simple Bigger is Better isn't sufficent. If we look at the way businesses rise and fall, we can get a similie that seems to me to be satisfying on a deeper level. For example, Circuit City was a huge corporation that rose to power and then collapsed in bankrupcy. Said the CEO, It wasn't necessarily doomed "had we woke up sooner...It wasn't obvious in sales figures, but the rot had set in...The world is always changing, and you can’t rely on your past accomplishments.”
That is so very different from the biggest corporation being insurmountable! And the same story is played out in the death of a lot of big companies. A sense that the big companies become sluggish, complacent, ineffectual in their ability to respond appropriately to the competition. So I wonder if we can model something like this into a 4x game in such a way that it is fun, easily comprehended and improves the game.
As a first draft of this idea, a player's society (or some smaller business units?) could have a cumbersome variable, a construction time delay or cooldown based on it's size. Meetings and conferences must be held, and delays and run-on expenses.
A second version of cumbersomeness is that the large companies are essentially failing to adapt to their current environment, falling behind the curve as new ideas are implemented by competitors. This seems like it has to do with Technology. So it might be appropriate to think of modelling a substantial penalty to research and development, based on size. So bigger empires would take a hit to Research point production.