Top 10 Worst Europa Universalis 4 Idea Bonuses

Most modifiers/bonuses you can get from ideas, policies, events etc. in Europa Universalis 4 gets actually useful when they are stocked up enough, even when they are ony really usable in special cases. But it's hard to deny there are just too many of them, which is really what makes the game unnecessarily complex. Especially what new expansions are essentially doing is adding even more bonuses, the game is just becoming way too bloated for the new players.

(All screenshots are from EU4 Wiki)

So, we will examine the ten types of bad ideas and see what's really wrong with them.

10. Narrowed Bonuses of Better Ideas

The national idea/decision bonuses are usually justified by historical accuracy, this is why certain nations have stronger bonuses, representing historical "success" they had. But I don't like this justification, because idea groups already represents the direction a country goes. I am not entirely against national ideas as they add some historical flavor, but I am seriously aganist just picking up some nations for being "chosen ones" as if they just developed independent of the material conditions.
Giving smaller bonuses is one thing, but it is even more slap on the  when you have the more specialized versions of same ideas. Like when you only have admin. tech. cost bonus instead of just tech. cost bonus or infantry cost bonus instead of regiment cost bonus. This especially gets worse with naval and maritime ideas, sorry for saying this Paradox but naval battles aren't just that deep, the side with more ships just wins 95% of the time, so I seriously don't get why devs try to make something look more complicated than it is.

9. +X Leaders Without Upkeep/+%X Available Mercenaries

These two bonuses share the fate of becoming less useful with the new patches. The former was never that useful anyway as military points just come in spades, but the latter took a serious hit when base mercenary rate was considerably increased and the mercenary spam became somewhat less useful as time goes on. This reflects another problem in the design philosophy, the devs like adding bonuses a lot but very reluctant on quitting old useless ones.

8. +X Legitimacy/+X Horde Unity/+X Devotion

Legitimacy is mainly affected from events and the situation of your heirs, which largely depends on luck. Horde Unity is pretty much depends on how aggressive the player is. Devotion already can grow slowly with a stable country and choosing right heirs and not as drastic as the other two modifiers. And with the new "strengthen government" feature, a small steady increase is pretty useless.
But it gets worse, because they become completely dead bonuses when government type changes, unless the idea alreadys adds the bonuses of other government types. One particularly bad case is the national ideas of some Mesoamerican countries, having legitimacy bonus despite being tribal democracies. I guess Paradox likes cruel jokes.
If they gave a modifier that seta minimum level of legitimacy instead of steady passive increases and if bonuses change accordingly with their respective government, it would be much useful. As it s now, they don't fit to the design of the modifiers. Ironically, the republican tradition works very well with passive bonuses, in fact it works so well the game is very reluctant to handing you out that bonuses.

7. +X% Income From Vassals/+%X Vassal Force Limit Contribution

Another example of game design contradicting with the bonuses given, you can't just increase random parameters and expect things to get better. Vassals are usually meant as an alternative way to acquire new land and the game discourages the players from having too many vassals or making them large enough to make these bonuses actually matter. Besides, the game has now tributaries if you specifically want to milk resources out of a country. Outside of very specific setups this bonuses are near useless and setting up the bonuses such a way does not justify the resources you have to spend to get them.

6. +X% Global Tariffs

The colonies give way better bonuses than tariffs, no competition. And keeping your tarrifs low is how you keep your colonies happy. I colonized in most of my campaigns and the game didn't affect in the slightest when I ignored tariffs entirely.
From this entry forward, we will encounter bonuses that would either be trivial or too powerful if they were increased to absurd amounts. Even with something like +100% or +200% increase, tariffs probably would barely make up for your colonization costs.

5. -X% Reduce Inflation Cost/ -X% Cost of Reducing War Exhaustion

These two bonuses just doesn't justify the resources spent to get them. Reducing inflation cost 75 admin points and you have to spend 400 admin points to get the idea that decreases the cost by %10 so to justify your spending you have to decrease your inflation more than 50 times, which doesn't happen even in full-length campaigns. A similar math can be done for war exhaustion, expect it is more trial because you spend dip. points and the game discourages the player from doing so with absolutism mechanic.
Well, you can ask, wouldn't they be sort of useful if they were higher? No, because much better passive bonuses already exist. Getting even a small amount of monthly reduction bonus just pretty much solves all your troubles. Manually reducing inflation/war exhaustions are designed to be costly panic buttons, so making them cost absurdly cheap would break the design.

4. +X% Prestige From Naval Battles

As I said before, naval battles are very basic in EU4. Everyone brings their ships, one or two encounters happens and the winner side basically controls the sea during the war. So a slight prestige bonus from naval warfare is not useful at all. Prestige bonus from land battles on the other hand is useful for an aggressive nation, even when bonuses are small it adds up as you encounter many, many land battles. Bonuses of similar situations doesn't just translate well to each other, yet Paradox just keeps adding bonuses anyway.
The most offensive thing about that bonus is that it makes naval idea group unnecessarily even weaker. Why not just give a flat increase to prestige instead, it makes sense within the historical context too.

3. -X% Morale Hit When Losing A Ship

Now, most bad bonuses are just extremely trivial,  too specific or have objectively better versions. . This bonus encapsulates all these, you know the drill, the naval warfare isn't just that detailed.
The reason why this bonus is especially terrible because it is deceptive and shows everything wrong with devs' obsession with overly narrow bonuses It makes the game far more complex than it actually is. Just look at how important it sounds, but sorry, these bonuses just doesn't make the game deeper.

2. -X% Migration Cooldown

Migration mechanic is only available on extremely specific conditions, conditions that are very undesirable for the player and even when conditions exists, having this bonus gives a very minor bonus, it's pretty much a dead weight idea. The problem here is more about the modifier affected rather than the bonus. When you put player into a situation that player needs to get rid of, making that situation somewhat more fun doesn't alleviate the problem. EU4 needs to drop the idea of putting players into very tedious circumstances only to just reaching to the conditions of a regular campaign. And thankfully, the way the game is going forward shows us that, the game actually did change most of its most tedious parts but unfortunately Native mechanics still remain as failed experiments for the most part.

1. +X% Chance of New Heir

I admit, the placement on the entries is somewhat arbitrary, you can swap some entries with each other and the list wouldn't be worse in the slightest, but this one definitely deserves the top spot. It's completely useless even when you are a monarchy. In one of my campaigns, I remained without a king for near 20 years, despite having +200% Chance of New Heir.
It's also uniquely bad because we don't know what the effect it has, we don't know what the chance of heir is anyways, it is a bonus that increases an invisible modifier.
The sad part is, a much better version exists. The game introduced more government types with guaranteed succession something this bonus tries to represent. This bonus has really no reason to exist yet it's literally everywhere, the game is just plagued with this one. It's truly baffling to see the adoration the devs have towards this bonus.

Dishonorable Mentions:

•  May Recruit Female General/ Increased Female Advisor Chance/ Some Other Very Specific Custom Ideas: These bonuses don't give any mechanical advantage to the player at all, but they just exist as Custom ideas, so player knows what they are getting into if they choose to select it.
• +X% Hostile Core-Creation Cost: This bonus is often just annoying and not very useful to player. But it exists to represent the countries which were not easy to conquer and it works decent enough in that regard. And it was actually useful to me for fending off big scary countries a couple of times, so I guess I have a soft spot towards it.

In conclusion,more numbers doesn't make your game mechanics deeper and subtracting stuff from your game is often as important as adding. Especially if your game is all about modifiers, you shouldn't act carefree about them. Fake complexity can drive a lot of people who would otherwise enjoy your game.
This article is written thanks to my dearest Patrons and special thanks to: Alexandra Morgan, Laura Watson and Spencer Gill.