Personally, I think we should be aiming for more questions about currently airing shows in Japan, not fewer. My reasoning is as follows.
Our biggest goal right now, in my view, should be to attract more experts (which for the moment I'm taking to mean people who have fairly broad knowledge of a large number of series). These are the sorts of people who can help us get more answers on questions, get questions off the unanswered tab, and are likely to be very valuable contributors overall. We have a serious problem at the upper end, that almost all of our top users have been here since private beta. Among all users with 2k rep or more, the latest account creation date is December 26th 2012, which is just 2 weeks after we started in private beta and 1 week after public beta began. Going down to 1k rep, there's one user from February, but everyone else has been here a while. That will be a serious impediment to growth as we go forward.
This indicates to me one of two things: Either we aren't reaching the people who know a lot about a lot of anime series, or we are reaching them but they aren't staying around (at least not for very long). To get people to join and stick around, or even to find us, we need to be showing up on the things they're searching for and have lots of content that they find interesting. For experts, I believe (though I do not have strong evidence for this) that this is mostly currently airing shows. If we focus on things which recently premiered in English-speaking countries, this might increase our overall traffic, but the majority of those hits would be from casual viewers, not experts. It isn't particularly a problem to get hits from casual anime fans, but they aren't the type of fans we should be targeting. On that basis, I think we should try to get more questions about currently airing things in Japan and other popular things among hardcore fans rather than casual fans.
It isn't enough to just ask the questions, though. We also need to get answers to them. If we're using these as seeding questions, we need someone to post an answer. It might be a good idea to coordinate in chat or on meta at the beginning of each season a couple of shows which we think we have strong experts in, i.e. people who have read the manga or have been following the series for a long time or something to that effect. Otherwise the questions will probably just go unanswered for a long time, which defeats the purpose.
EDIT: In light of my recent answer at What can we do to get more answers?, I'd like to clarify that I don't think that answer and this answer contradict each other. We can simultaneously move away from particularly niche content and ask questions which are more interesting to experts. It's a hard balance to strike, but we need to focus on currently airing popular series and long term popular series which appeal to broad audiences. This means looking at places like MAL's list of popular anime and finding cases of popular anime which could get more questions while still being answerable by our users here. There's a lot of room between series like Naruto/Bleach and some of the niche stuff which gets asked, and a lot of that represents areas where we are prepared to answer questions but aren't getting as many as we could be.