A proposed solution to this would be tapping the encoder in the Beam FX menu to change from "size" to "zoom" — and then allowing a 0-100% setting.
This was tested using the Chauvet R1x Wash, which is a flexible wash fixture with an 11 to 48 degree zoom. On the tight end, it is respectably spotty, but on the wide end, it's an expansive wash. The zoom level obviously has a major impact on the appearance of the beam, and is a huge appeal of this particular fixture and many others. So it would make sense for zoom level to be its own fixed parameter in the Beam FX page. Currently, the only other way I'm able to manually adjust the zoom level of this fixture is via live edit.
Fixed zoom control would also be useful in the static position picker. Perhaps you want to zoom in on a distant mirror ball or wedding cake. Perhaps you want to have your fixtures washing a very broad area. You get the picture!

Can I remap the focus level (in the static position picker) to control zoom instead?
Cheers!