There are a couple of questions hanging heavy over this idea of independence. More than just being possible that a safe, familiar story will be trotted out with characters that are easy to draw, at the smaller publishers; some co's stay derivative in the vain hope that fanboys will choose their version over the ones already on offer. Another aspect of independence in the world of comic book publishing, is the ability to find a market outside the traditional news stand. Pacific Comics sold to the direct market and were succesful for a time because of the established artists working on the books. But that is not true independence, unless the other requirements are met.
To further put the lie to the notion that you can 'judge a book by its cover' and recognize an independent comic by appearance alone; consider the case of Plop!. Talk about walking like a duck! The most spasticated duck you've ever seen in your life. But still not an independent comic. Further, Marvel Comics once put out a tasteless and short-lived book called Mort the Dead Teenager. They may have been riffing on the popularity of independent weirdness but it remains resolutely a comic put out by a mainstream publishing company.Another interpretation of 'independent' is the publication of comic books outside the stranglehold of the North American and European market. When they can barely make a sale, who is mean enough to deny these comics the status solely on the basis that they may carry advertising or have investors waiting to see some return for their money.