My God. I cannot endure more than half a minute of that (skipped to the middle).
There's nothing inherently wrong or bad about the method Eastwood chose to apply - the second article Zarathustra cited was correct in that the public perception would be entirely different if it was, for example, Downey Jr. at the DNC, or Schwarzenegger at the RNC - it's that he stutters more than an old coffee machine and thus gives the impression of being an old, insecure and senile wreck. Most people cannot look past that and focus on the content, and I don't believe they should, because it does tell us something about the people running the Republican Party.
The method is entirely dependent on the delivery of the words, and Eastwood failed. Saying that this was the plan along, the creation of a viral campaign which, supposedly, is a "feel sorry for"-jerkoff in favour of the Republican Party, is most likely a sad attempt at saving face. An opportunity to broadcast some rhetorical bombs to the entire nation, and instead waste it on something which you hope will make people vote Republican because they feel sorry for Clint Eastwood; it's not the genius kind of madness, to say the least. I seriously doubt any spindoctor would place such a bet.