Unit ranges are considerably higher than "standard" and units have the ability to move, attack, move again, and attack again in the same turn.

It makes for a "faster" game with a more fluid strategic situation. You may think it favors the aggressor [easier to move into and conquer large areas quickly] but with modification it could actually favor the defender by making it easier to mass defensive units in response to an attack.

I am considering modifying my game's units to make the units more mobile in this way. [It shouldn't take 40 years for my pikeman to move from my capital to my front line.] My only concern is the radical effect these changes would have on the "exploration" aspect of the game; if it's possible to cover the map in 10 turns everyone would be Christopher Columbus by 3500 BC.

What we need is a two-tiered movement system. Units should [essentially] expend NO movement points to cover terrain already in the civilization's map. [Given the time scales of the turns, it IS dumb for units to take so long to move over roads they know.] Moving into "black" tiles on the map should cost more than it does now. This would have the effect of making both internal and external unit movement more realistic.

The question is: can this be done? Can the movement point cost of a given hex of terrain be different depending on whether it is "black" or not?

The effect on game balance would be dramatic, I know, but in a GOOD way. Essentially it would improve the AI's capacity for defense on its own terrain, even if no other AI changes were made; it would be possible for the computer to mass units to defend and counter-attack essentially for FREE, while you need to spend movement points to attack.

It's also a good way to put a higher premium on spying, exploration, and diplomacy - it will be extremely difficult to attack what you haven't spied out beforehand.