I simulated a full game with Better BTS AI 0.2, the replay is attached
565AD: Shaka dows on Asoka a non-neighbour but it is a religious war.
950AD: Hannibal becomes a vassal of China (why)
1060AD: Shaka DOWS on neighbour Egypt (why)
1070AD: Shaka and Egypt make peace in 1 turn (how)
1140AD: Ramesse and Asoka dow on China/Hannibal
1140AD: China/Hannibal dow on Mansa (border war! but wise?)
1150AD: Bismarck dows on China/Hannibal(Bismarck is being squeezed)
1170AD: China/Hannibal break away from each other
1180AD: Shaka dows Asoka a non-neighbour (why)
1200AD: Isabella dows on Shaka a non-neighbour (probably religion)
1210AD: Asoka, Isabella and Shaka make peace in 1 turn (how)
1295AD: Shaka turns on neighbour Ramesse (border war!)
1300AD: Asoka and China declare peace but Asoka still at war on Hann
1310AD: Ramesse and China declare peace but Ramesse still at war on Hann
1315AD: China becomes vassal of Bismarck and thus at war on Hann (border war!)
1315AD: China/Bismarck at peace with Mansa because of vassal agreement
1350AD: Ragnar dows on China/Bismarck (in centre hotspot)
1355AD: Shaka making good progress in border war with Egypt
1370AD: Bismarck making good progress on Hannibal
1385AD: Bismarck/China make peace with Hannibal
1390AD: Hannibal makes peace with Mansa
1460AD: Ragnar looses war and becomes vassal of Bismarck/China
1470AD: Hannibal looses war and becomes a vassal of Asoka
1485AD: Shaka wins war on Ramesse extending border territory and peace declared
1495AD: Ramesse becomes a vassal of Shaka
1515AD: Shaka/Ramesse declare regional war on Isabella
1570AD: Shaka wins border territory from Isabella and Isabella becomes a vassal
1595AD: Bismarck/China/Ragnar DOW on Shaka/Ramesse/Isabella (emerging east/west conflict)
1655AD: East/West war over with Bismarck making some border territory on Shaka
1728AD: Bismarck/China/Ragnar DOW on Asoka/Hannibal (why)
1734AD: Shaka/Ramesse/Isabella DOW on Bismarck/China/Ragnar(good)
1750AD: Good border wars between vassal rival
1766AD: Bismarck making good progress in border war with Ramesse
1776AD: Wars over leaving Bismarck and Shaka with a little more border territory
1796AD: Bismarck/China/Ragnar peace with Asoka/Hann with Bismarck making more centre territory
1800AD: All old world wars are over and now new world race begins
1824AD: Shaka/Ramesse/Isabella DOW on Bismarck/China
1851AD: Ragnar liberates new world to Roosevelt
1855AD: Bismarck looses significant ground in border war with Shaka
1856AD: Bismarck/China break apart
1860AD: Shaka/Ramesse/Isabella make peace with Bismarck and vassal him
1860AD: Bismarck turns on broken vassal china (border war in centre)
1878AD: Shaka(west) captures China city (east) how?
1878AD: China becomes vassal of Shaka
1891AD: Mansa gets on with wonder construction
1892AD: Mansa at war with Ragnar in new world (how)
1898AD: Shaka/Ramesse/Isabella/Bismarck(west super power) DOW on Mansa
1908AD: West war against Mansa over with Mansa loosing old world territory
1918AD: Mansa looses old world territory to Ragnar in only old world war
1924AD: New world/old world war begins between West super power against Ragnar/Roosevelt
1934AD: Old world war status quo but new world war favours west super power
1934AD: Ragnar/Roosevelt become vassals to western super power nations
1936AD: Ramesse breaks vassal arrangement with western super power because of new world territory gains
1941AD: Ramesse returns to the western super power as a vassal (good idea!)
1941AD: Mansa liberates old world city to Asoka/Hannibal
1943AD: Mansa almost non-existent in old world but has large new world territory
1945AD: World war between west/east including Mansa verses the West
1959AD: World peace with the western super power making good progress
1959AD: Ramesse breaks free of western super power and continues war on Asoka in new world(not a good idea?)
1969AD: Western super power DOWS on Ramesse (punishment)
1974AD: War over Ramesse gains in new world but looses in old world
1978AD: Massive world war
-Shaka head of the western super power wins a diplomatic victory-
These are my comments:
1) sounds like a heap of fun
2) there seems to be a mix of border conflict and religious conflict early
3) a couple of questionable war decisions
4) The early phases of the old world wars need examining
5) The interaction between the old world and new world is complicated and possibly produces questionable war declarations
6) This game started with low number of civs and thus was not all about border wars. If you start with high numbers of civs, border war is much more emphasised earlier.
7) This behaviour of Better than BTS seems consistent and reasonable.
Cheers.