Is it better to focus on one stat for your ruler?

[Gojak_v3]

Or should you try for some balance between the stats?

I mean I know one stat is always gonna be dominate because of education trait.

[AC Denton]

Well obviously it entirely depends on your character, their situation and what you need to do. The entire game is about being flexible, no guaranteed one way to do things.

[VipreRX]

The spouse you pick should be done to balance out your stats, their strongest being your weakest is a generally good thing. You can also use lifestyle traits to balance them out. There are ones that provide up to I think +5 for certain stats based on prestige and piety for example.
So I guess the short version is a bit of both really, you want a strong main stat with aids for your weaker to make them suck less.

[Razorblade]

Tbh, stats only matter conditionally.

You only need Martial if you're fighting an overwhelming enemy that you can't win against without a god-tier general.

You only need Learning if you're the Cultural Head and are really want a certain technology soooner rather than later.

You only need Stewardship if you're jonesing for money.

You only need Intrigue if you're plotting against another high-Intrigue character.

And you only need Diplomacy if you're trying to diplomatically vassalize your neighbors en-masse.

So realistically, you're rarely going to have to legitimately worry about your stat spread. I tend to just ignore stats, choose an Education solely for its boosted XP gains for lifestyles of its type, and choose traits that are either Virtuous for my religion, or will otherwise universally benefit me (like Temperate with its health boost).

[dwarfpcfan]

Assuming you don't get assassinate or catch the great pox or something similar and your ruler isn't afflicted with congenital traits that reduce his health. Your ruler should always live well into his 60s

That's more then enough to finish at least 2 trees in once of the focuses even if you're not getting any exp boosts.

So finish 1 primary education focus tree, then switch to either stewardship or learning after and you can have a smoother reign