I'll key in on some of the corps of which shows I have actually seen in person.
Crown: I'd like to see the same thing I saw this season: face-melting brass. Of course, percussion needs improvement, and when that is done, they'll be absolutely undeniable.
Spirit of Atlanta: I absolutely love the musical choices and such, but a different theme would also be nice to see.
Blue Devils: With all of the hate towards Blue Devils' design these recent years, I find it funny that I've actually quite enjoyed them more-so than their earlier years. I absolutely loved the 2011-2012 shows. I don't know if anyone else agrees with me here though.
Blue Knights: It was a nice change of pace this year with the design and musical choices. I'm a HUMUNGOUS fan of mellow, rhythmic music--so needless to say, this show was one of my favorites this year. The theme was a little abstract for me (unless all I was supposed to get out of it was circles and balls), but it didn't really matter much to me considering I enjoyed the music.
Blue Stars: Just a heads up, I'm a Blue Stars honk, so I'm pretty much going to talk a lot about them. How I became such a fan?--Well, it was their 2008 show that made me a fan of DCI in general, leading to my (rather unhealthy) obsession with the activity. When I think of DCI, I immediately remember and hum the first hit of the Le Tour show that got them back into finals.
That being said, I really miss the "happy melodic" music that was played in 2008-2009 years. It really makes shows memorable and quite enjoyable for others that don't care too much for the Blue Stars. I feel that the Blue Stars are trying to find their "identity"--like the ones Spirit, PR, Bluecoats, and BD have. The identity that I think they are trying to form is somewhat of a "dark" identity. The recent years (2010-2013) have a rather serious nature about them, including 2012. Don't get me wrong, I loved 2010 and its theme (I'm a sucker for Glass and minimalist music), but I feel like they're trying to mimic the success they had with that rather dark theme too much, and should try to head in a different direction.
I enjoyed 2013 more than last year, and since next year is the 50th anniversary, I really think they should make a show about the history of the corps. Oh, and bring back the red plumes (not necessarily the helmet, but just the plumes), even if its just for the anniversary year. I think it would help bring back their "identity" that they're struggling to find. I think this was said about BS for 2011-2013--they have the talent, they just need the show.
Troopers: Okay, I love these guys. The emotion from this show is just unbelievable. I'd really love to see more difficulty in the book though (but I think this was a rebuilding year from the previous year). Although, they were smart to fit the difficulty of the program to the members and decided to beef-up their book as the season progressed, rather than the watering-down that some corps have to do. It's funny, actually: I was SO excited that Blue Stars made it back into finals, but was SO disappointed that Troopers missed out on finals by only .15 points (and I don't even consider myself a Troopers fan). There is something magical about this corps this year that makes everyone embrace them. Hold onto that.