I assume you have recently acquired your RV. I can't offer a 'better' solution but can tell you this method has worked well for hundreds of carbed RVs. Yes, it looks kinda crude, but it works.
My RV-6 is like yours, O-320 E2D converted to 160hp. I'm on the second filter in the 19 years I've flown it. When I replaced the filter a few years ago I too was determined to find a more elegant solution.....I ended up with the same arrangement that worked so well with the first filter. Van had no doubt been through the same thought process and decided to stay with the simple solution.
In regard to the cracked base plate, verify that there is adequate space between the cowl and airbox to allow full motion of the engine during startup and shutdown. If the cowl is making contact with the airbox, the plate will eventually crack. No contact, and the plate should last a long time.