This.
"Gee, I wish I had put points in intelligence instead of blunt, I didn't realize it was a useless skill" - Morrowind. Or Oblivion. Take your pick.
Don't like the way you made your character? Start over. That's the fun part of the game.
No, no it is not! Wasting 50+ hours because of an "It seemed a good idea at the time" descision is NOT fun.
In previous games, you could always choose to start leveling up a new skill if you don't like your old choices: Sure, the leveling system might try to punish you for such folly, but there's nothing stopping you from continuing to increase skills.
However, I don't like the OP's suggestion either. I just wish there was a standing stone/altar/Aetherial Altar you could go to once per level and re-choose a perk.
Changing perks is NOT "Learning new skills" - Learning skills is learning new skills. Choosing perks in Skyrim is your mark on the heavens, and path through the stars. You need the option to change your stars.
The Smithing/Enchanting perks are an aberration next to ALL other perks in the game because their benefit lasts long after the perk stops being useful... But EVERY OTHER PERK in the game requires the perk invested to remain useful. And if you never get a chance to use a perk you selected, then it becomes worthless, and a loss of a level.