How about some extra gold-silver-gems in starting area to help us research further through the tech tree before the game ends? Simply bloating the size of the map to make it last longer would be inelegant and tedious, right?
Maybe there could be some design involving mountains and water to create narrow border areas so that wars have a certain likelihood of winding down after only modest gains. Or giving people a defensible rich starting area, plus lower-value peripheral regions to fight over in a less crucial way.
(maybe, I don't really understand MP civ4 map design and its strategic implications)
I think that just having a map on the bigger side of things would address these concerns. Doesn't have to be huge huge, but big enough that one player is not likely to die early in a rush, and so people have more time to react and go for a final blaze of glory world war if the smallest fry is being invaded. I'd rather see that then premeditated chokepoints.
To be candid, unless I generate a torusland map with alternative dimensions I can't get that number of tiles and the minimum distance for a 4 player game.
I don't have a good sense for what a typical map gives in terms of dimensions and distance (probably why the map for PB34 ended up so bad...). Is there a script that would give a rough ballpark of 'more' rather than 'less' distance?
In short: To get large distances without abnormal amount of land, you need water. My maps for PB60 and PB63 had similar amount of tiles per player, but very different distances.
And the problem in a four player game is that Tiny is designed for three as per most map scripts, and if a fourth player is crammed in most maps I've generated fail the distance measure, and on a small map, you will have significant more than 130 tiles per person. Like, 200+ tiles per person, because the water level doesn't make that great a difference.
Now, there are map scripts that can give you a reasonable land form which meets the distance measure, such as Highlands, Global Highlands, some Tilted axis versions, that give decent naturalish looking maps (and the resource balance is far easier to do by hand so don't worry about that element of the map generation), but the other choices are maps like Wheel, Inland Sea and Donut which are incredibly unnatural and lead to very game-y situations.
Again, being candid, I would suggest that a Highlands map set to Cylindrical would be a good base map for four players, set to Cylindrical and Small. This does give quite a bit of land but all players start a reasonable distance apart but you can interact. This also gives the benefit of naturally occuring "choke points" rather than me arbitrality making it fit.
I'm fine with most maps.
I liked the PB89 map from civforum.
2 donuts with 5 players each, a green ring, island before the coast and "clear" borderregions.
If you want to costum built a map, maybe you could get some inspiration from this map ?
And I don't know If the mapmaker here know it, but the PAE Mod (best cIV Mod) has a mapfilechanger, which can add new lines/rows to the map. Maybe you could use that the create bigger maps ?