Well, ya know, if Europe is too crowded, it's always possible to get rid of most of the players in that area.
I know, that goes against every RFC player's instinct, which is to
add playable civs: the Catalans, the Basques, the Austrians, the Alsatians, the Hessians, the Lubeckians, the people who live at No. 12 Karlstrasse in Bonn ...
But seriously, if you didn't add the Portuguese and the Spanish and the Dutch (and the Catalans, the Basques, the Austrians, the Alsatians, the Hessians, the Lubeckians, etc.); and if you got rid of the English, the French and the Germans; in other words, if you had just one post-classical "European" or "Western" civilization, it would take care of the 1upt traffic problem quite neatly. If it wouldn't be a problem in China or the Middle East it certainly wouldn't be a problem in a one-civ Europe.
It would be conceptually tidier too. Meaning no disrespect, but how ethnocentric is it to act as though the cultural chasm between the Germans and the Dutch is as wide as that between the Inca and the Babylonians; but that everyone between the Gobi and the South China Sea is exactly alike?
Rhye also mentions a speed issue with even so few as 12 civs. So, if people are going to insist on Spain, France, Germany, England, and the Netherlands (at a minimum; they'll also insist on Portugal, I'm sure, and probably the Vikings as well; and then come the Catalans and the Basques and the Austrians ...) what does that leave? Apparently, it leaves five to seven slots before things get problematic. Be conservative and pick only three ancient civilizations and one New World civilization; that still leaves only one to three slots for: the Greeks, the Romans, the Russians, the Japanese, the Khmer, the Ethiopians, the Mali, the Ottomans, the Arabs, the Persians, the Mongols, the Americans, the Carthaginians and others I'm sure I'm forgetting.
Even if the game is redone, so that there are no more than 12 civs in play at a time (which I guess might be one way of keeping things manageable), is it really balanced to restrict half of those possibilities late in the game to a somewhat largish peninsula on the back end of the Asian landmass?
Put in only one Western civilization—not the "French" or the "Germans," but "European" or some such—and a lot of choices do not get closed down.
....
Look, okay, it's a suggestion that has to be made, even if it's not to be implemented—and even if it gets me flamed. Otherwise, I like Baldyr's "mergable units" suggestion, though it loses much of the "tactical" element that is the 1upt rule's only saving grace. I like better his suggestion made in another thread that units be stackable, but that battles take place on a minimap where they aren't, but that's almost certainly not technically doable.