I dont mind losing brothers early on when i dont have equipment or skills to defeat some tough enemies.
But if i put a ~2000 gold worth of body armor and ~1500 gold worth of helmet armor on a brother, i dont expect them to die in 2 hits. There shouldnt be a standard non unique enemy that does that. I invest myself into leveling and equipping these characters, if they are supposed to drop like flies, even with almost the best possible gear in game, then whats the point of RPG elements of the game.
No, i dont find that fun at all. Definitely not as the basic game balance. At higher difficulty levels, sure, im all for giving people that if thats their thing.