Sacrosanct
Legend
I think the thinness of content has played into this.
But honestly I think it is largely the nature of the bounded system. I've been very vocal in praising it and I'm not retracting that. But two years later it is kinda done. And when they do put out a new class or spell they feel very mechanically shallow. I'm not going to try to defend my opinion here. It is my opinion and is shared by my group, so that is good enough. But for examples sake, a new class is still going to be the same prof bonus plus their prime attribute to hit one simple AC. I'm eager to get back touch ACs and frequent ability damage, and size modifiers, etc etc etc.
Things feel more distinct and customized.
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If your group wants that and has fun, you don't need to defend that position. That's the only reason you need. For me, it's the opposite. I was really turned off by 3e for the same reasons you like it (funny how that often works that way with subjective preferences lol). For me, all those things slow the gameplay down way too much for my tastes. For my group, we prefer the game focus on the flow of the adventure, rather than have it a glorified constant mathematical process with swords thrown in

I'm not THAT much of a math nerd....