Anybody that renounces their US citizenship for any reason is no friend of mine. Templeton was still a great stock picker, and I admire that. I don't demand perfection from anyone.
From a moral standpoint, legally avoiding income taxes is no worse than having a cestoda removed from your intestines.
The guy is gone and all you have to say is that he did not pay taxes? Come on, you could probably do better than that, don't you think so?
http://www.truthandpolitics.org/top-rates.php#fn-7 The link is to a table of marginal income tax rates in the US since the Fed came into being. In 1962 the top rate was effectively 87%. I have a suspicion that this influenced his decision. If his income at that time qualified him for this privilege I'd say he was paying more than his fair share of taxes.