FWIIW J is moving in this direction as well; the last release version of it (807) needed a special build for older intel hardware (they subsequently made separate binaries for older hardware). AVX has been around since 2011/2012, so it doesn't seem like that big a deal.

Admittedly I myself have older hardware kicking around I see no real reason to upgrade, but AVX is such a big win on array processing you might as well make it a dependency for the kinds of use cases Shakti or J get used for in business.