The skill the MC rejects is the one I want to see someone else use well
One thing I really enjoy is when a skill choice makes sense for the protagonist without becoming the objectively correct choice for everyone.
Say there's a skill that boosts mana regen while you're standing still. A solo caster who spends every fight dodging should probably skip it. But I'd love to later meet a mage who picked it, has a tank keeping enemies off them, and can afford to keep casting long after the MC would be running dry.
Same description, same limitations. Someone built around it and got a useful result.
It makes me more interested in those skill selection scenes because I can actually imagine where the rejected options might have led. Sometimes I spend longer thinking about those than the thing the MC picked.
The payoff I'd want is the protagonist recognizing that this other person made a good choice too. Maybe even needing their help in a fight where their own build struggles. Let me spend a few chapters wishing we'd taken the other skill.