There is much that can be done with selecting the starting conditions that will speed the end-game considerably, yet still allowing all out war and growth.
The thing is to have a firm understanding (this means TF, since he creates the games) of exactly what the cause & outcomes will be when certain changes are made. Of paramount importance is the land distribution and starting conditions. I, and probably others, can just examine a map and pretty much read the details of the late game. It's almost all mathematical (I'll roll my own eyes for all of you, hehe....), but simply put, the number of land tiles, and their distribution, can allow a massive + fun game without the huge tedium of overwhelming farming.
Personally, I like big maps.... 8,000 to 10,000 tiles. But unless the map is set up carefully, this will result in a tedious end game and probably cause lots of people not to finish.
There is another option, too, to allow the fun of a large map without as much time and tedium... a city limit. Noughmaster first proposed it way back when, and he suggested 10. But the 254 city limit (with one pet city) is quite arbitrary... there is no reason why Matrix/TF could not just state "100 cities are the max in this particular GOTM" This will also cut the scores by about half, which is fine... and the early CTW players might drool about.
So big maps can work, and populations (e.g., tedium and time) can be controlled through terrain/map format, and/or reducing the number of cities allowed.
There are lots of other ways to influence the game, too, but I'll stop here for now

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Big map = FUN
Long long games = not as fun
Small landmass = faster games
254 cities = tedious game
Smaller landmass + Big map + fewer cities = faster + FUN + less tedium