I have to agree with Saktoth about the ruling systems design. It might look somewhat lame, but at least it spices up PW.
Dynasty is already ruled by the clans with most planets anyway (GBC and NGO clans are practically the ruling elite). After our recent sales to Cyber now OSS clan is climbing into power positions also. So it would actually work quite nicely. Clan with most planets nominates grand duke (which runs affairs on all planets and elects government), all clan leaders become local dukes that run affairs on the planets belonging to that clan. Obviously, only central government can sign treaties, but the clan dukes have a share of faction bombers and other goodies. Also, their planets can not be directly traded without them giving consent.
Cybers have been ruled by M6 as long as it was active. Oversight should be >1 person though. I think each clan should have a representative in the oversight, which votes on which clan would run Cyber affairs. On the other hand, oversight should be invisible to the other factions, and even the members of Cyber should not know WHO represents which clan (anonymous forum thread for oversight? Would be ultimate lulz as oversight has no idea WHO ARE OVERSIGHT).
Machines should elect their government based on some metrics like ELO or whatever (no elections) with watchdog timer removing the useless ones if they end up in power. Democracy is not "machiny" enough imho.
Empire should have the enter plot thing 100%, and when emperor is overthrown his account should be closed (as in the dude is actually killed lolz). Lots of power - lots of risk. Although, the Emperor should have the capability to poke one player per day to figure out if he is plotting against him - if that player indeed entered the plot then his account is cancelled, and if he did not - the message is posted that %username%'s office was turned over looking for conspiracy, but nothing was found. That would discredit emperor to some extent. Also, all planets owned by empire lose 1 IP when that happens. For the plot to actually overthrow the emperor, the total number of conspirators should be >50% of the faction. Elected officials count as 10% each.
Liberty's system is OK imho.