Home Improvement is one of my favorite sites, so I hope it does come out of beta. That said, it is showing relatively steady indicators (visitors, traffic, question rates, etc) rather than growing indicators, so we think it needs more time to hit critical mass.
What we generally see with a (non-pathological) Stack Exchange site is nice, steady traffic going kind of horizontally for a while, then, at some unpredictable point, we hit critical mass and POW the site starts to grow every week. When this critical mass point is hit, the horizontal curves all tilt up and to the right and start climbing inexorably. This is the right point for a site to come out of public beta.
We're happy to cultivate a site in public beta for as long as necessary. We're also happy to do whatever it takes to help a site get to critical mass. For many sites, we're sending top participants to conferences to evangelize the site. Some sites, like diy.se, really just need another dozen regular contributors to break out of their boring horizontal trends and start climbing up and to the right.