For me how it sounds when behind the shield as well as reducing unwanted reflections is a big deal. Plastic does a very poor job in these areas. Unwanted reflections get sent up and bounce around like sonic bullets, getting into the mikes.
At my church a generous guy with wood skills built a set of hinged sound baffles NOT made of any plastic. The wood, cloth and sound absorptive material absorbs sound and reflects much less than any plastic or hard surface I've played behind. Of course you can't see the drummer except from the neck up - which is fine with me.
The next best thing I've experienced is one of the mixed material, total enclosure like this
. A bit of an isolating experience musically and puts more weight on the shoulders of those providing and mixing monitors for the drummer. It's also $3000 (I think) not including the Avion monitoring solution that is necessary for this to function.
There's definitely a need for better products in this area. Come up with a winner and the first thing you'll want to do is market to churches in the U.S.