For my class (USNA 2012), it seemed like there was more interest in submarines this year than in the past. I didn't hear of a ton of cases where aviation wannabees were forced to go submarines. I did see quite a few cases of people wanting to go SWO who were made to go to a nuke interview and became Nuke SWOs. In my company, everyone save like 2 people got their first choice (i.e. about 35 out of 37 people got their #1 choice). And those guys that didn't get their first choice had nothing to do with aviation.
In my situation I put NFO as my first choice and subs was my 3rd choice. Although I was near the top of my class and was an engineering major, I wasn't even considered for a nuke interview due to the fact that few people select NFO out of the Academy. A more common situation you will see (well, at USNA anyways; I'm not sure about NROTC) is people who are made NFOs because there aren't enough pilot slots and barely anyone puts NFO as #1.
If you do get selected for a Nuke interview, my advice would be to do your best and simply tell the admiral that you would like to go aviation and why. Don't bash on the sub community (he's a 4 star nuke admiral after all!), but try to convince him that the Navy would be better served with you in the pilots seat. Letting him know that you were a part of a flying club, or have met with other aviators would probably help. I know a few guys at the academy that were able to convince our Commandant to let them fly and not even get a nuke interview. I'm not sure how different the selection process is for NROTC.
I see that you are a third class midshipman right now. I wouldn't worry about selection at this point. Just do your best in school and learn all that you can during summer cruise, CORTRAMID, etc. I can't tell you how many people were interested in doing one thing for the first 2-3 years at USNA only to find out what they really liked was something else (usually PROTRAMID/CORTRAMID got people interested in a certain community).
Good luck with your endeavors!