Great point. A sketch is just a rapid visualization of an idea… bad idea = bad sketch, no matter how technically proficient. I’ve seen so many technically fantastic sketches of bad ideas that companies tried to make because the sketch was ‘hot’, and many technically horrible sketches of fantastic ideas that were never made because people couldn’t ‘see it’.
As pointed out above, you are going to school to learn. There will be those who maybe have a jump start on you, but some of those guys flare out because they are used to being the best. When someone like you eclipses them, they take it hard 
Go to the best school possible, work your butt off, and make it happen.