Using "Maybe a" when you have a nullable value is smart, not "clever". It aids maintenance and readability, not hampers it.
Using pattern matching is the same.
Haskell builds on mathematicaly simplicity, which makes things hard to grasp at first. This may be mistaken for cleverness.
Unless I'm misunderstanding you -- can you give an example of something clever in Haskell?
let loeb x = fmap ($ loeb x) x in
loeb [ (!!5), const 3, liftM2 (+) (!!0) (!!1), (*2) . (!!2), length, const 17]
I've seen cleaner and more readable code in production haskell, but this sort of thing happens enough that I'm very cautious.
With years of Haskell experience, I rarely encounter code that is hard for me to read. This is a good counter-example, and is not typical code.
I read 10 lines of Haskell code roughly as fast as I read 10 lines of Python code -- yet the 10 lines of Haskell code can pack much more useful information.
So Haskell is a great tool for more efficient communication between programmers, who can write shorter messages to each other to convey the same information.
But, then you gotta remember, "worse is better" (New Jersey style), and Go is worse. New Jersey style: (1) be simple in both implementation and interface (2) correct, be correct as long as it doesn't make it more complicated, simple is more important than correct (3) consistent, when you can be consistent, do be, but simplicity is more important and (4) completeness, be as complete as you can, but realize completeness can be sacrificed for any other objective.
I think C and Go share a lot of New Jersey style -- Go is great in simplicity (remember simple isn't easy). I think Go will continue to go quickly because of these attributes.