There are only three leader trait combinations unassigned:
Charismatic + Creative
Industrious + Philosophical
Organized + Protective
Assuming there is only supposed be one leader per combo, and knowing that no combo is really "verboten" (proof: Boudicca's Aggressive + Charismatic combo), then there can only be 3 new civs or just 3 new leaders or something inbetween. But...
If a new leader trait were added to the game that would raise the number of combinations from 55 to 66. We have "only" 52 leaders right now; but I think 66 leaders could be both interesting - and perhaps cumbersome - how much choice does everyone want before things get out of hand? I dunno but at some point it all becomes spam...
Adding new leaders is one thing, and there's certainly room for some more, but more civs and their UBs and their UUs? I think we are near the very end of what is reasonable/viable in the context of 6000 years of global history.
Some suggestions to "wrap things up":
1) Add a host of leaderheads for some civs, like the Celts and the Native Americans, that represent different tribes in different regions at different times in their respective histories. That fills tons of gaps without wading through tedious specifics that most people won't care about.
2) Add the Goths as a civ under the same logic that Celts and NA civs are in the game; have 3 LHs for the Goths, one for before they split, and then one for the Ostrogoths, and one for the Visigoths.
3) Add Poland and Hungary. With 2) above Europe is saturated
4) Add one new leader for the Arabs, China, Japan, Rome, Spain, and the Vikings (renaming the Vikings as the Scandanavians).
5) At least 3 more generic naval units: tramp steamer (push the landingcraft unit into a special coastal-unit-only catagory), a sail+steam ship of the 1800s, and WWI "dreadnought", and maybe a WWII cruiser?
6) Add the Pacific Islanders (Polynesians) under the same logic as Native Americans, and add 3 or 4 leaders of reknown for the main island cultures found across the Pacific.
7) Add one more civic to each catagory of civics. There's room and there are viable good ideas out there.
8) Add a new leader trait:
Adventurous - for those leaders who were courageous in times of peace and exploration.
All naval units start with Navigation I, Scouts and Explorer's start with Sentry in addition to their other attributes; Observatories and Stables are at double production speed.
9) Add Ancient Israel, The Kongo, Burma/Siam, and the Hittites...
10) And finally, add the legendary civs of Atlantis, Amazonia, Hyborea, and one or two others - with the default setting that
they are not normally available unless you open the Custom Game screen and select them! So those players who do not want to see too much fiction in their game won't have to do anything special to avoid these civs.
Of course, now I am betting another expansion isn't likely so all this talk is probably just moot... But fodder for modders!
