I've always thought Balgruuf should be high king, he's the best Jarl of the lot, keeps a good city, and cares about his people, his hold, his guards, his family, etc.
No war going on and no thalmor? Balgruuf. He's a great peacetime leader. Issues in his hold are addressed in a timely matter and his citizen's safety take priority over most things.
Actual current events still going on? Ulfric.
Balgruuf is an isolationist.(He supports the secession but dislikes Ulfric) He doesn't want to deal with problems outside of his hold/nation unless absolutely forced to. This is not a good stance to take when you have an openly hostile nation plotting your demise and have shown that with enough time, they will succeed at killing you.
How about balgruff becomes highking and he leaves his position of jarl and as his champion and thane you get the job. This is like being (((((((((SPOILER))))))))))) sheogorath in the way you can control the hold and every day there are bandit raids and you get more for going yourself (((((((((SPOILER END))))))))))
And you can make a house in the outskirts of whiterun city! cool idea and its not horse armour its a win-win situation!
No war going on and no thalmor? Balgruuf. He's a great peacetime leader. Issues in his hold are addressed in a timely matter and his citizen's safety take priority over most things.
Actual current events still going on? Ulfric.
Balgruuf is an isolationist.(He supports the secession but dislikes Ulfric) He doesn't want to deal with problems outside of his hold/nation unless absolutely forced to. This is not a good stance to take when you have an openly hostile nation plotting your demise and have shown that with enough time, they will succeed at killing you.
This. Although I'd have chosen Ulfric anyways. At least he seems to care AND he has guts against the Thalmor, while Balgruul changes sides and allies himself with the Imperials as soon as Ulfric asks for help.