I suspect the lack of a .223 option probably is due to one of two things. The first would simply be that since the .223 would require a different bolt head arrangement they decided not to include it in the first stage of the launch but will come sometime later when they expand the line. The second possible reason could be a feeding reliability issue between the Impulses bolt design and the AICS .223 mag's.

Savage has never offered Axis/110 rifles in .223 setup to take AR15 magazines for the latter reason - the feed lips on AR mags simply aren't compatible with their bolt design. If you look at a Mossberg Patriot (basically a copy of a Savage 110) in .223 that uses the AR mags, you'll note that the bolt head has a very unique and obvious difference that allows it to work with the AR mags. Could be a similar issue with the 223 AICS mags.

This is the one negative attributes of a "one size fits all" action design. There will always be some cartridges that simply can't/won't feed well from it and it usually ends up being the smaller diameter cartridges because the actions are primarily designed around and sized for standard diameter cartridges which account for the vast majority of rifles they will build and sell.