In my very personal view, appointments give much more quality to the game than elections.
Appointments are burden and responsibility to the one who has that power and always create some in-game dynamics/tension/obligation, in any case leave deep trace to in-game play in one way or another.
Appointments enforce responsibility to the one appointed as well, as there are no ideal claims, and appointee always feels some pressure about it.
The main problem with elections are that they are "ideally fair", they are objective, everyone has chance etc. etc. Not once I heard from leaders who received public complaints about their bad performance "you may be right, but nobles decided on my position, and you can bring your dissatisfaction to next elections" or similar, instead of trying to justify his/her action, and that is point when any further discussion stops. Elections are ideal, leaders are elected in fair way, so they do not need to defend their plans much, if you dislike them, do not vote them next time... Of course, not everyone behaves like that, but one form or another of similar approach can be seen often. That plainly kills potential in-realm political fights.
another problem with elections is that... many new players have good chances. I think that is adverse for both game and those who get some positions too early.
bm cannot offer people real money, golden coins, all our satisfaction come from small attachments to our signatures, titles, some feuds and when new players get them too easy they both do not appreciate it much and lose motivation for further play. much more satisfaction comes from position earned after long time of good work, and those who are too impatient almost certainly will not become even average contributors to gameplay.
additional problem comes form the fact that some position require really tangible in-game experience and some players realize that only at the moment when they get such too easy title, which creates lot of frustration, that is really not fun, especially for them.
monthly elections... endless system messages create apathy.
elections weighted with prestige, representative votes, such kind of elections would make much more sense, because tensions would migrate to domain of reason of such imbalance, be it prestige or large numbers of vasals who are represented. however, i almost never see such elections.
fair and even voting is simply tasteless in my opinion, and those tasteless speeches that comes around that just confirm such their nature. there is nothing in middle age that would support equality among different ranks and reputations, and though they are still useful for some positions voting, it is really bad to see equal voting for all council positions.
of course, there must be natural in-game way how to replace appointed positions, but that belongs in my opinion to another domain - need to create tensions and balance of powers between realm council and landed lords, and that cannot be solved by elections mechanics.
"democratic" elections, similarly to "too much peace code" in my opinion is trying to mitigate consequences of lack of internal conflict, while I believe that should be cured at its source - by creating balance of powers that will not allow untouchable postions.
so, my answer is - any type of government that has no too much "democratic" (equal vote) elections is good...
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