Interesting, but why the KL DSL? It seems you could have either used something like OpenCL, or, went with a language like Go, Dart, of haxe.
The rationale for creating KL was that we had some specific goals, and we couldn't find an existing language that did everything we wanted - the requirement of being high-performance _and_ easy to use was critical. We also had security concerns (we started out as a browser plug-in), so it also had to be pointerless. Given that we have a fairly narrow scope (writing high-performance operator code), we decided the best path was a DSL. If we didn't have the security concern, we would have stuck with C++ - but that wouldn't have had the lower bar to entry that KL has.
My co-founder who wrote KL still thinks we were crazy to do it - 'the world does not need another language' :)