Well to be fair, Miller wasn't a full time staff writer until season eight. He started on the series in season five as an unpaid intern and worked his way up. I believe when "Smallville" finally concluded, he was an Executive Story Editor. It was also through "Smallville" that he met Geoff Johns which is how he got his current gig in DC Comics. So the man has risen through the ranks to get where he is now.
"Argo" started today. Haven't had a chance to read it yet, but will give my thoughts tomorrow.
Edit: I had time to read it tonight...and loved it. The Lois and Clark shower scenes were fun. Lois had something from Ferris Air (looked like a cheque, but don't think it was, I assume she gets this from her adventures with Lana). A nice surprise cameo from Blue Beetle, and Micheal's stolen Legion ring calls back the user, he attempts to find out what it means from Clark, and they get both pulled back to the future...discovering a crumbling Metropolis....while poor Skeets gets left behind. This keeps getting better and better.