No, I simply assume the trainee pay will dissuade some applicants. If you can attract a bigger pool of applicants you should get more at the top end to pick from, simply because you have more in total.
Many of the controllers I work with didn't start out wanting a career in ATC. They were looking for a change or just looking for a job - they fell into it rather than actively seeking it. You need something that will attract the casually interested as well as those who desperately want it, because both are as likely to have the requisite attributes.
We've done a very average job of recruiting and training over recent years so being able to cast the net wider is surely no bad thing.