Having a simple syntax might be fine for computers but syntax is mainly designed to be read and written by humans. Having a simple one like lisp then just makes syntactic discussions a semantic problem, just shifting the layers.
And I think an complex syntax is far easier to read and write than a simple syntax with complex semantics. You also get a faster feedback loop in case the syntax of your code is wrong vs the semantics (which might be undiscovered until runtime).
And I think an complex syntax is far easier to read and write than a simple syntax with complex semantics. You also get a faster feedback loop in case the syntax of your code is wrong vs the semantics (which might be undiscovered until runtime).