After playing this game a couple of times and getting a couple of endings, I think the biggest thing that could improve the game to me as a whole is having the 'main' story events be more relevant.
For the rest of this thread I'll refer to 'Main' events as events that happen regardless of where you are, and usually on a specific day, (ruling on laws, specific happenings, policies, national holidays, etc.). I am not referring to any events that happen on planets, or any mood wheel assassination attempts. I am also not referring to any event that involves sniffing out the 'secrets' of the game, as I think that sequence of events is very good and doesn't need much improvement.
LLTQ had main story events that threw out hooks. Named characters would appear in main story events and directly ask you to do things. Or other people would ask you to do things about named characters. This would happen even if you've never met or heard of them. You would end up getting tidbits of lore about important characters regardless of if you actively did anything to try and approach them. This would lead you to wonder about them, even if you never interacted wtih them again. Given the linearity of the story in that game compared to this one, it's understandable that Zorana has less of this, but it is very noticeable.
In this game, however, most of the 'main' events involve faceless people and policies. LLTQ had these as well, but they didn't feel like they occured as frequently. Sure, these events do affect the story by shifting faction/elector approval, but they tend to not have any direct visible impact, and feel a lot less personal then similar events in LLTQ where your ruling would directly disenfranchise a named character. Almost all of the events I can think of off the top of my head do not involve ANY named elector.
The result of this is you never really get any information about anyone unless you choose to go and visit them. I don't think this is necessarily a bad decision, but it would be nice if more 'main' events involved actual named characters which could sort of act as hooks to go vist their planet if you haven't already.
Another big missed opportunity in these main events is that your rival emperor/empress candidates don't really show up all that much? Even just hearing what other emperor/empress candidates would say about existing issues I think could provide a lot more insight into their character, and having them actually try and sabotage you beyond mood wheel assassinations and nabbing electors would be fun.
Also, tangentially related, I think it would also be a bit more interesting if more of the 'main' events were actually dangerous. As far as I can tell, you mainly die in this game from doing quests you are not prepared for, or getting mood wheel assassinated. I can't really think of any 'main' events that just occur that have the possibility to be lethal/injure you (other than the main events that involve sniffing out the 'secrets' of the game, which are appropriately dangerous). This contrasts with LLTQ where sometimes, events just happen and try to kill you without you having to have done anything to deserve it. LLTQ maybe went a bit overboard with it, but one or two dangerous 'main' events that happen and require specific skills (or making sacrifices like losing an advisor or something) would amp up the danger of the game.
I don't want this to come off as overly negative, btw, I absolutely adore this game, and think it is even better than the first LLTQ (which was one of my favorite games), but I think this specifically is one area where I feel like LLTQ exceeded this game.