I didn't say complex mechanics are bad, just that if you require your players to sit through a training session before they play the game, then you've probably

I didn't say complex mechanics are bad, just that if you require your players to sit through a training session before they play the game, then you've probably designed your game poorly. Elden Ring has rather complex mechanics, with all of the gear and ability interactions, but the tutorial is mostly just the gameplay, and the skippable tutorial at the beginning is just a short section of gameplay with pop-up tips.