Is it bad to apply for the same Master's degree program in consecutive years? I am an undergraduate majoring in computer science. I want to apply for a top Master program in the US. I have done the GRE test and most of the other things required. 
I am currently doing research with my professor so there might be more publication to come but it will be later than the application deadline.

I don't know if I should try to apply this year. There are certain things I am concerning (my GPA might be lower, my reference letter might not be as strong as before, there might be more applicants in the next year) .

There is one thing I don't know how will the admission office work on. 

If I failed the first year, will it be a negative factor for my application the next year (say if I could been admitted originally, but because I failed the last application the year before so I am not accepted)?  

will it be like I revealed too much information so they can see my change between the two years(for example they found I didn't make much progress like the years before in that year)? 

will they compare the two applications(for example they found there is lots of change in my SOP, like my life goal changed largely)  or will they be processed totally independent?

Just say I have 25% possibility to get admitted, my situation might be better or worse the next year. If I failed this year I will reapply the next year. Is it worth a shot to apply this year?
I applied twice in two consecutive years for graduate school. Some universities do not track or compare current applications to previous ones, so those schools likely would not notice (and thus would not care). 

Some institutions do track if you've applied previously. This isn't a deal-breaker, but then you'd want the year gap to show you made significant gains and improved your application. 

Thus, my advice would be: if you want to apply this year, go for it. If you don't get in, find a job or internship and/or take classes that let(s) you improve your application significantly. Develop new skills, showcase an ability to be successful in more advanced projects. 

Then, were you to apply that next year, don't mention that you applied to that institution before and got rejected, but do emphasize all the skills you gained during your time off. Talk about how that year prepared you to be a successful graduate student in your essay, make sure the skills developed during that year are clear on your resume and in your description of projects (if there is one).

Edit: If you are concerned the graduate program is a reach for you, you might consider taking a year off to build your skills anyway. You could probably make a decent amount of money for that year, and you may be less stressed and able to get more out of graduate school.