Well, I'll say the doctors oath giving medicine skill is a God Send for leveling medicine. Without that it was just not goin to happen and the game would end with my medics having gone from 120-150 or so. However it still comes in too late to be very useful or impactful in the game. In warband surgery is much better because you can quickly get the max level on you MC and have the full benefit the whole game, preserving more of your best troops early when it matters most. In Bannerlord, it's nice to get 275+ medicine but by then you're so good and defeating the AI and have so much access to troops, it's just not going to change the game.
Charm has a few very good perks, even though the skill it's self still makes me do a double take at how stupid it is: So the skill is I get more relations when I get more relations and how I learn the skill is getting more relation? Yo Dog...... But there are so many ways to get relation that charm basically levels it's self and I can forgive it. Also, the way I start my character to not waste any points starts me with 4 charm. I love firebrand though!
I'd say the main appeal of a high INT main character is just the convenience of covering the roles and being able to use family members (who can also have high INT) as you clan party leaders, rather then roles in you party.
I also like 3 end and 3 cunning om MC to get the mounted patrols/keen sight combo, but this take a very long times now too since scouting is no longer bugged. Still I get it eventually and even at the last leg of the game being able to kart around a couple faction of lords is great!
One thing I guess I must say though, is that painting the map isn't the end if you don't want it to be. You could always leave you kingdom and take it on by yourself! Max medicine and keen sight/mp might really make a difference if you suddenly are cut of from all the villages and are fighting a mega faction.