Malgus lost to a group of the best fighters in the Galaxy, he didn't exactly get moped to the floor.
1. You don't know what Marr looks like lol and 2. What does looks have to do with anything? Malgus is definitely Charismatic, he inspired tons to stand behind his empire knowing full well that by doing so they would be betraying a galactic superpower and leaving behind everything they once possessed.
And no, Acina is a terrible choice. She is extremely passive (which is practically how she came to power in the first place) and I think the fact that she appointed that retard Lorman to minister in the first place speaks wonders of her administration, she had not control over the closest things around her. The only reason she is not dethroned is because the rest of the council presumably died in battle or killed each other. She allies herself with us because she knows we can dethrone her too, she is weak.