Any disadvantage to multiple applications? I am considering applying for PhD programs in CS. I've been reading about the process, reading the sorts of things that programs want and I would say that I am an OK (but not stellar) applicant. For instance,  I'm missing some math classes that I could take next year. I've also been working in industry, so I could certainly get more involved with research (I'm working on a few in-progress papers now). I think that if I waited a year I would be a more competitive applicant. Is there any particular reason not to apply now, see how I do, and then potentially reapply in a year? If anything, applying a second time (as a stronger applicant) would show that I really want to do this. Right?
I don't think there is anything wrong with this, as long as on the 2nd application a year later, it is made clear that something changed in the year prior. This could be additional courses taken, higher test scores (GRE for example), etc. I think if your application is legitimately improved over the year, no one would ever have a problem with this, but a potential reviewer might be annoyed if they receive the same application year after year without notable changes/improvements.