I try not wipe out factions unless forced to, I try to keep older FMs to use as generals and Governors and keep younger ones back in Rome or Sparta or wherever mycapital happens to be.

I'm not really a good enough player to do many of the unit houserules, except in my Rome game, where my mostly historically-composed Legions absolutely slaughter stacks of Gauls and Sweboz, expecially when defending a city.

I can't use Force Diplomacy as I'm playing 1.1, otherwise I totally would.