It is possible to comment applications on the ICANN web site but it is also possible to provide a simple feed-back regarding something you've liked - or not.
You can sumbit your feed-back on the "New gTLD Program Feedback" page.
At the moment I write this, there are 4 comments (which are not very optimistic by the way) but hey give anyone the opportunity to give an advice. I would say this is fair-play, thank you ICANN.
Note, ICANN reserves the right to remove feedback that does not adhere to "ICANN Expected Standards of Behavior" and "ICANN's Open Comment Forum Process and Standards".
You can feed-back on the new gTLD program feedback.