A capital ship would last longer than a fighter within a sun's corona. As such it should be a valid tactic.
Though I've seen a barge park directly on top of a sun and chill there for longer than I cared to stick around and watch. That in my eyes is worse than a cap ships using the corona as a tactical advantage.
I think that stars should act as they do now, EXCEPT that when you bump into them, they should instakill you, the same as planets do.
How can a capship survive in a corona? The same way it can survive antimatter and small weapons fire - extra shielding and armor.
Be kinder than necessary, because everyone you meet is fighting some kind of battle.
J.M. Barrie