Because it is game-breaking in any game that isn't meant for idiots to play. You can choose mixed character but no one will guarantee you'll be able to progress with such character. Not every build works well in RPG.
As for review itself, sounds like it is written by some kid who only played Skyrim. Steam review sections is full of similar reviews.
Just like Dark Souls or Arcanum or some other quality RPG, this isn't game for everyone. If you're into Elder Scrolls kind of RPG, maybe its better to avoid it.
Even Diablo makes it clear to you that by choosing Sorceress you won't be good in melee. Yes, you can put points in STR and VIT, but will you be able to beat the game at higher diff. levels? I don't think so. Talking about first two games in Diablo series, not this modern lemonade for idiots.