It is easy and straightforward to make parentheses in EmacsLisp and other dialects of Lisp less visible by putting a less bright Face on them:

 (defface paren-face
   '((((class color) (background dark))
      (:foreground "grey20"))
     (((class color) (background light))
      (:foreground "grey80")))
   "Face used to dim parentheses.")
  (add-hook 'emacs-lisp-mode-hook 
 	  (lambda ()
 	    (font-lock-add-keywords nil 
 				    '(("(\\|)" . 'paren-face)))))

Now they are fairly unobstrusive and stay modestly in the background, when you read Lisp code. IMHO this reflects their role in Lisp code: Lispers seldom look at the parentheses, they look at the indentation.

See ParenFace; this has already been done.

CategoryParentheses CategoryDisplay CategoryFaces CategoryHumor ParenthesesAppearance