I attended both prelims and finals at UIL and was amazed at the level of playing by all of the bands. Regarding the different style bands (Coppell and Ducanville versus the BOA pack) I think you really need to analyze the entire show. While many of the BOA style bands march extremely fast, complicated drills, they do little playing during these moments. When sections are featured playing difficult music it is generally when they are standing still. I noticed several bands would march for up to 90 seconds before playing their first notes as an ensemble. Either sound effects, drums or a sectional solo played while the majority did some amazing drill move. And one band only played as an ensemble for a total of about 4 minutes........I timed it. They didn't make finals, but what is the music judge supposed to judge when you aren't playing?
If you noticed, Coppell and Ducanville play from start to finish pretty much as a full ensemble, spreading across the entire field with their large bands. And they play with an incredible balanced sound, especially considering how far apart the sections are. Both groups march very clean drills. Sure, they're not running around in drill formations but they are playing their instruments non-stop. So while some bands are practicing to perfect their difficult drill moves other bands are working to perfect their difficult music.
Now I agree, BOA style bands are generally more crowd pleasing and fun to watch. But the point of UIL is to reward those bands that are teaching their kids how to play music well while marching. It doesn't necessarily reward the show designers for a cool concept the way BOA does. A band that plays very well will generally do better than a band with a great show design at UIL.
However, some bands like Marcus and Bell have figured out how to impress both BOA and UIL, and I predict other bands will follow suit over the next couple of years.