I don't disagree with you. My problem is, DMs aren't properly taught in the DMG how to do this, and the game doesn't give good advice for how to use skills in creative ways. We DO get advice on using skills. We have xanathars to help with tools. But there isn't enough of a focus on creatively using skills, and because of that, leaving it up to the DM just isn't satisfactory to me.
There are three reasons any rule exists, and even just checking off one of these reasons is good enough to justify existence:
- It makes the game more fun when engaged with
- It draws attention to the different ways you can use the game
- It highlights what the game is about
5E is about being a heroic adventurer. I would like more rules, or at the very least, guidelines, that highlight that. And when I say rules, I'm not speaking in super strict mechanics exclusively. Give me concrete examples, like most games do these days, of mechanics in the game being used to achieve unique things.
And above all of this, class is the most important part of your character mechanically in D&D. I don't see any single flaw other than page space to having a brief section talking about creative uses a barbarian might have for their skills, or a ranger, or a rogue, or a wizard, etc. It's not enough to know that these skills are available to my class. It's not enough to know I can make ability checks. I want the game to highlight for me potential things I can do, and then encourage me to go off and do them.