One of my biggest gripes about warfare in CIV is that you can move your army half across the map, deep into enemy territory, without any consequences whatsoever. Armies have to be supplied or else they will perish. So I propose that armies can operate only so far from a friendly city or base. Look at the way air units currently operate in CIV3 and you'll see a good example of what I am proposing for land units. When you set a air unit on a mission it can operate only withing so many squares of the city, career, or airfield in which it is based. This should also be true of land units to prevent armies from marching deep into unknown territory... that is VERY unrealistic. When an army operates beyond it's borders it needs to be connected to a friendly city or base by a road or rail line. Look what happened to the Germany army at Stalingrad when it was cut off and surrounded. Why doesn't this ever happen in CIV?
I also want to say that I think some units, such as scouts and explorers, should be exempted from supply lines. This is because scouts can basically live off the land through hunting and gathering, but it isn't realistic for an army to live off the land like that.
To summarize my proposal: I think you should be able to send your scout all over the map anywhere you want, but you should not be able to do this with your army. If you want to send your army somewhere it needs to be connected to supply lines so that it won't end up like the German 6th army...
I also want to say that I think some units, such as scouts and explorers, should be exempted from supply lines. This is because scouts can basically live off the land through hunting and gathering, but it isn't realistic for an army to live off the land like that.
To summarize my proposal: I think you should be able to send your scout all over the map anywhere you want, but you should not be able to do this with your army. If you want to send your army somewhere it needs to be connected to supply lines so that it won't end up like the German 6th army...