I joined the Dart team because I thought is was a worthy and important project that could beneficially impact a very large number of people. I _do_ think about these things, they're quite important to me. The goals of more sane semantics, more optimizable structure, and better toolability and tools are to me, and a lot of other engineers, incredibly reasonable and beneficial. That's actually the entire point of the project is to be more reasonable and beneficial than the alternatives :)
If fact, I think I'll use that as my informal Dart tagline: "Dart, reasonable and beneficial!"
More seriously, Dart is created by people who think that JS is broken and we need an alternative. I hope you're not claiming that that's really an unreasonable opinion, and that the only reasonable point of view is that JavaScript should always be the only language used to develop web applications. I'm sure reasonable people can disagree about the degree of brokenness of JavaScript, and about different solutions to the problems.