Foremost, let me come clean: my company develops Japanese language vocabulary study iOS software. I have every personal reason to gain from such a popularity contest.
That out in the open, I agree with jkerian's point that such questions aren't good for the community.
In my own experience, I made software because I wasn't happy with the other options - they all had something wrong with them (by my criteria). Interestingly, when I went around to various forums and websites to introduce/promote my product, I was met with (in many cases), "We're not interested, we use X for that" (X = usually one of the products I had felt wasn't up to the job). People -- particularly online -- seem to become very defensive of whatever they personally used as a tool, and without good objective criteria, it is very hard to address that.
Language learning is a constantly evolving science (nay, art?). By allowing such questions, you'll end up with a few "super questions" that receive many votes, becoming highly SEO'ed, and draw a lot of traffic. And the "winners" of that post -- even 2 years from now -- will continue to receive business, even if their product isn't indeed the best.
In short, the answer to something like "why can't men say わ at the end of a sentence" is pretty much timeless, whereas a better dictionary or piece of software may come out in a year -- so unless those questions come with a time expiry (not build into the stack exchange sites as I understand), it's not a good idea for innovation.