Trouble with feudalism with free maintenance is that every AI player switches to it and never switch back at least on Monarch level of play. This actually makes game far easier for human players as it seems that AI overproduces units and then is forced to lower its science level to keep up with maintenance costs.
Result is that AI players are backward in tech, with tons of obsolete units. Somewhere at middle ages AI science is so crippled that it almost makes no progress at all compared to thriving human republics.
Out of subject, to fix feudalism I have modified it to communal corruption and 5/3/0 unit support. All other stats remain the same. This way feudalism still stays a lot behind communism (war weariness, much lower upkeep), but gives something new compared to other govts. AI also seems to use it sometimes, depending on situation but still mainly uses in rebublic that is in my opinion most competitive government for AI to use in game at early stages.
-- Migo