**The below comments assume we are all aware that use of anamorphics is no longer something we do in order to maintain resolution since most anamorphic lenses degrade the resolving power more than the act losing pixels through cropping**
IMO use of anamorphic for the majority of our purposes should be undertaken with the fastest and sharpest taking lens available - particularly on smaller sensors.
Since our use of anamorphics is an aesthetic choice rather than an attempt to maintain resolution, there is not much point in shooting anamorphic if the dof is so deep, and with no separation between in/out of focus parts of the frame, the aesthetic is no longer noticeable.
I think one of the main reasons anamorphics like the SLR magic 1.33x have had such a bad time is that firstly it works best with wider lenses and smaller sensors, and slower apertures (meaning dof is so deep the already weak 1.33x look is even less obvious). - it's a disaster combination and why such lenses don;t command much respect from anamorphic purists.
I feel if a anamorphic requires the taking lens to be closed to f5.6, on an m4/3 sensor the anamorphic is not up to the task of the sensor it is being used on, the user loses a lot of the 'look' from anamorphic. And adds hassle, weight, and unpleasant optical degradations into the equation. The end result often just looks like spherical cropped to 2.35 with a gaussian blur and CA added in post.
to me a rough guide / criterion similar to this should be considered in order to make the job of shooting anamorphic a worthwhile choice (without unpleasant degradations to resolving power, CA, etc), while maintaining some type of anamorphic 'look' :-
1. using full frame the anamorphic needs to be able to accommodate an 85mm @f5.6 or faster, or a 50mm @f4 or faster
2. using aps-c / s35 a 50mm @f4 or faster, or a 35mm @f2.8 of faster
3. using m4/3 a 35mm @f2.8 or faster, or 25mm @f2 or faster
4. gh4/4k mode will need a 30mm at f2 or faster, or a 18mm @ f1.4
5. s16mm (bmpcc) will need a 20mm at f1.4 or a 12mm at f1.0
The lens speed can be 1 stop slower for every lens focal length step, for instance using an f-135mm lens on full frame would still look anamorphic set at f8. a 200mm lens would still look anamorphic when closed down to f11.
a separation between in/out of focus areas is a critical attribute you need for anamorphic shooting to be beneficial for most uses.