I think a lot of people miss the fact that Ron IS clever and that Hermione is NOT always right. Hermione is exceptionally intelligent of course, but her knowledge is mostly based on being able to remember and process a lot of written information. Ron’s views are mostly based on real life observations. Both sources have their limitations (Compare their attitudes to S.P.E.W; Hermione sees a principle (slavery) that is wrong and wants to correct it, Ron sees the actual behaviour and preferences of the house elfs and doesn’t see the need for change. Neither of them is completely wrong).
Hermione draws the right conclusion about the problems they’re facing most of the time, but she doesn’t necessarily know when to stop pointing that out. This is where Ron’s strength comes in. He’s intuitive (something Hermione is NOT) and knows when to just let things be rather than harping on about what should have been or ought to be like Hermione. I think that, as the two get older, this means that they will balance each other very nicely.
I also think that while Ron isn’t as verbal as Hermione, or as good at make sense of difficult reading material, he has no problem understanding her. The fact that he, in his blunt way, doesn’t accept what she says on face value doesn’t mean he’s dumb!