For me, player skill certainly comes first.
There are a few primary (and related issues) that arise for me:
1. Few players have the intellect to figure things out their INT 18+ PC might.
2. Few players can role-play their CHA 18+ PC well enough to justify what their PC should be able to do.
3. Some players are much more intelligent than their INT 8 PC is, but they play their PC like a very intelligent creature.
And so forth.
Under such circumstances, I allow rolls to help players who can't match their PCs, and FORCE rolls when the players are out-performing the expectations of their PCs.
Some people might find that heavy-handed, but if you have a dump stat, then PLAY it!