I tend to play either tiny city-states, or "difficult" very large and sprawling/diverse empires, notably the Seleukids.
If the former: it depends on my expansion strategy, or not. Typically this will mean focusing on civics (primarily for minmaxing money/trade) and/or oratory (for minmaxing various other currencies). And, of course, taking research efficiency to its cap ASAP.
For the latter, however, I'll focus on religion, especially to mitigate the inherent diversity penalties and thus save the empire from internal collapse. And either:
- take it all the way to Militant Epicureanism so I can give myself a stability boost by desecrating a temple whenever I run into (or foolishly create!) an otherwise insuperable problem (e.g. a downward stability spiral following an "over-successful" war!); or, if I want to make it a bit harder again,
- getting some oratory (loyalty etc) bonuses instead to try to offset said problems. This is preferable because imv temple desecration is a bit too easy to exploit, especially in already diverse empires - maybe the benefit should have a cooldown, and/or have a temporary happiness penalty to all "desecrated" pops within the nation, or some other nerf.
Meanwhile "maximizing" research efficiency for such a diverse empire case means consistently improving from its dire start of 30% or so. Just keeping up with competitors is highly satisfying.
This latter strategy used to work well with vanilla. But now I'm playing the truly fabulous Imperator Invictus mod, which takes IR to a whole new level of sophistication. Unfortunately, I still haven't figured out how to get any decent conversion or assimilation going (of the order of 1% or more), even in the capital province. Even pulling all the stops out (laws/policies/pop mixes etc), more than Seleukos himself ever did despite his hilariously consistent ability to outwit the Babylonian priesthood's cunning plans! Arguably this is exactly as it should be. But I'm still having trouble figuring it out a way around, short of converting my ruler - which carries its own dangers as well!
. Otherwise my next move is to play Ptolemy and see if it's any easier there under each of his three religious options: Hellenistic, Kemetic, or syncretic (Isis/whatever?)
[Otherwise I find Ptolemy a bit too easy: after defeating Antigonus, with my initial superior Navy and Aegean presence for naval range, I just go straight for the Antipatrids and and grab all those lovely Makedonian/Hellenistic pops.
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