In my code, where the binding forms would typically be longer than (a 1) or (b 2), they each go on their own line, and the editor will align them by their left parentheses. In those cases where the initialization form needs to be broken into another line, the editor will indent the continuation properly, and the 'terminating' parenthesis is actually a helpful visual cue that the form is done.

I haven't written any Clojure so I'm not sure how my brain would react to non-delimited forms (ie, the implicit pairs). I also don't know how Emacs handles the indentation for these, or whether in more complicated cases, my brain would have to work harder to group the binding forms. I read the Clojure specs on 'let' and it appears to be a somewhat different beast than the CL 'let'. In more complicated cases, it doesn't appear to be an apples-to-apples comparison in terms of parsing the 'shape' of the expressions.