The "brickfilming community" has never really frowned upon nor preferred any one technique or film type. It's sad when a well made film doesn't get a lot of recognition - but that sort of thing is inevitable in the era of YouTube. Generally, the community just prefers creators who are having fun, doing what they want/what they love - regardless of if they're following "trends" or one creative "direction."
There have actually been quite a few brickfilms utilizing non-brick built sets, although LEGO-centric films are still the norm. I, myself, used some of the old Harry Potter cardboard backdrops (included in the actual LEGO sets) for my Flick 'n Swish film. TheLoginProductions made the pilot of his Bat-Man series completely out of Minimates figures, cardboard/printed paper/wooden sets, and sparse LEGO & off-brand props! The Bat-Man: The Axeman's Jazz It really freed him up to take set designing more seriously - and break away from some of the brickbuilt "norms" of LEGO MOCing.
Doug Vandegrift's America: Outlawed and Pirates! both use an impressive amount of greenscreening and solid color backgrounds for sky effects, water, etc. If you really use your director's eye, you'll notice that some shots are completely chroma keyed with just a minifigure or prop visible otherwise! But he blends it so well, not many have pointed it out.
And, of course, there's Rübermachen; a former highlighted brickfilm of the week for it's creative use of model railway decorations as sets! This served as the primary inspiration for both myself and TheLoginProductions to do just what you're proposing, and break away from LEGO sets for more experimentation - and often times - more creative freedom.
It's frustrating to imagine gigantic ornate sets in your mind only to be limited by your supply of LEGO bricks. Going with a different medium can certainly help free your mind, and I'd definitely recommend it. Now that I've started experimenting with non-LEGO buildings - I doubt I'll ever fully go back. (Unless I REALLY want an "Out of Time" classic brickfilming look)
Go for it! And please share what you come up with! 
