I personally enjoyed some of the earlier iterations of government systems because it was more simple. I know there were quite a few folks who were really into it a few years later with the senate and what-not too, though I'll admit it just got a bit much for me to keep up with so I just sort of stopped reading.
So tl;dr I think this is on the right track and I support, and am looking forward to what you come up with. Also know that you've been there, done that and worn the t-shirt so you'll know the kinda things to think about. Further thoughts below, since it sounds like things are still in early stages:
Make the decision early on regarding how much "say" the Government has in the operation of other factions, obvs thinking law enforcement and fire department as the main ones. If it's to be a lot, then due care needs to go into who in the Government that particular responsibility stops with. I know this is why there was always some level of admin involvement in the form of a Governor for certain things, since IC decisions could heavily impact OOC enjoyment of the game. I'll use the example of the time when a Mayor tried to fire a Chief of Police, which would have caused untold chaos if nobody intervened.
If there's to be elections, I think make the terms long. We saw time and time again that regular new leadership basically meant an entirely new faction, which was unstable and chaotic. I know that the city manager position and the separation of departments / the mayor's office tried to combat this, and I'm not sure how successful that was (perhaps others who were around after me could elaborate 'cause that would be interesting to know). A constantly changing leader figure is also very fatiguing for everyone.
Remember it's still a game. I think that in the past, and in certain "other communities", it just went too far down the lines of being a bureaucratic, boring mess. Some people love doing paperwork and are fine with seeing their online lives as a second job, but I don't personally think that's sustainable. There are some paperworky things that you'll never get away from needing, but I think the focus should be on the roleplay and the experience far more than the function. I know not everyone will agree with that, but I'd rather have an active and stable government faction which stays that way because the players enjoy playing their characters, rather than one which just seems to manage a myriad of processes on the forums. I'm not saying make the government useless, but just make it interesting! Then we may actually have people who stick around.
If there's to be competition, or party systems, be careful of players getting too hyper about winning. Easier said than done I know, but I just think it's important to encourage people to enjoy the game and the stories rather than getting so involved and bothered about whether they'll "win". And yesss I know this also feeds into the wider problem of some folks having a problem with losing in general, I just know from experience that too much competition and things can get really nasty and stressful on an OOC level.
Stay fluid. You're in the fortunate position at the moment where nothing is set in stone and you can just sorta sit back and watch everyone's thoughts. People do have their own prerogatives for getting involved in Gov factions though; some people enjoy the creation and passing of legislation, some people enjoy having powerful characters, some people enjoy the in-game roleplay, some people see it as a popularity contest then disappear, some people enjoy the forum paperwork... basically just take opinions in context where you can. Creating a government which has function and purpose but is still fun to be part of in the game should be the direction, I reckon.
It's been a very long time since I roleplayed in Government on any server now, so I know that things have no doubt come a long way since the 2012 era. I'd be eager to hear more about what happened and whether certain things worked or not, purely 'cause I'm nosy and nostalgic. Also I ain't gonna pretend my opinions are the magic bullet here, far from it, just my two penneth from what I've seen before!