That's if one wants magic to be the first resort at all. And if one does, why would one play a non-spellcaster?
I don't mind magic being the solution when a mundane answer is possible. I just don't like it when magic is the best given the opportunity cost.
In 1e/2e, using your knock spell to bypass a door was a significant opportunity cost even when you were 15th level. For a 15th level mage in 3E though? Hell, even for a 7th level mage, knock no longer is a significant opportunity cost.
That's what I don't like.