And that sounds like an ad-hominem to me... the Foundation doesn't seem to be coming from an evangelical Christian viewpoint in general, and it's certainly not its stated mission.

Taking a person's most fundamental beliefs into account when trying to figure out what their true intentions are is not an ad hominem, it's common sense.

To give the classic Pragmatist example, people used to kill each other over the question of transubstantiation of the Eucharist. (...) It seems like insisting that one side or the other was wrong on this question is the wrong way to go, as nothing really turns on it and they're both saying roughly the same thing.

That's short-sighted. Nothing may really turn on the question of transubstantiation, but a there's a lot that turns on the cognitive processes that led millions of people to believe that a cracker is the body a magical Jewish half-deity.

I'm all in favor of "actually making things better", but the middle-of-the-road solution that the Templeton Foundation is (outwardly, deceitfully) espousing won't do that. Middle-of-the-road solutions are easy, they allow us to avoid sounding shrill, strident, and militant, but easiness is not effectiveness.

If people do end up making 'God' mean something vacuous, then there's no harm in letting them say it.

There is harm, because people who don't mean something vacuous by 'God' like to give the impression that they do to shield themselves against criticism. And thanks to 'pragmatism', it usually works.