The three a day limit is nothing new. Don’t know when it was implemented, but it was like that when I got here. I swear!
And it’s not counter productive. Two reasons.
One, it prevents flooding, and forces most of us to make our questions count. We have repetitiveness and whatnot, but this rule probably thins out a lot of that. (check out places like AnswerBag or Yahoo Answers, where you slog through a million questions and one out of fifty is worth reading)
Second, yes, the site is slow, but it has not always been as such. There was easily five + pages of questions a day a few years back. This three question a day limit is not what’s killing the activity here. That itself has to do with us being on Google’s black list, and now we’re hard to find. People leave quicker than the place gets filled. Mods or staff could explain this better than I, but the decreased activity has nothing to do with this rule. My first years on here are a testimony to that, in one session I could never get through all the questions.
The activity has picked up a bit though, in the last months.