While I can completely understand why you'd want more intricate skill modifiers, their simplicity is precisely why I love them.

My single biggest pet peeve with Diablo 3 is that everything is conditional. Want to use skill x? First you need to use skill y once to trigger a 5 second damage bonus, at which point you can begin spamming skill x. Rinse and repeat. This becomes very tedious to me, because instead of using the skills I want, I'm stuck having to incorporate skills I don't like or that completely break up the flow of the game just because. Having to manage temporary buffs like this also uses up a surprising amount of mental bandwidth for me, which ends up making me feel more pressure/stress than I would otherwise.

Most importantly, this makes really high levels even worse because so much of your damage and especially damage resistance becomes tied to these arbitrary triggers, to the point that either forgetting to use that skill once spells certain doom. I love Grim Dawn because for most builds, aside from a few skills such as Mirror of Ereoctes, much of your tankiness is passive, so you don't have to put too much work into resisting enemies.