What PC class should a well-designed ruler have?

[Rleonardh]

Than just go rogue for nothing but the skill set.
As you said a bad npc lord as no arcane or divine or so g for him.

That leaves in phb
Barbarian more hp and acf pounce, no one wants a conquer
Fighter go barbarian 1 at least, but hopefully you got people whom he can trust. But than again I cast hold person or charm person.
Monk saves only basically, be one with oneself
Rogue skillset you want, but you alienate good people as no one can trust a politician.