Agree with the line of thought that the transition needs to be phased out. Dravid is still playing okay and we haven't been able to find a replacement for Ganguly. If we had a stable, confident number 6 by now, I would have no hesitation in replacing Dravid. However, the fact is we don't after 2 years of trying 3 candidates.
As far as I see, there really is no need to rush things. If Pujara does become a long term option, and I would bet on his doing so, India can replace Dravid at the end of the next season. India has tours of WI, England, and Australia coming up and I would certainly be more comfortable having him there instead of two new comers. Tendulkar and Laxman still have whiles to go, so their phasing out can begin next year. It's always tempting to get into the mode of mass changes facing a retiring lot, but in this case the retiring lot is performing not just well, but as good as anyone in the world.
There is no need to panic and write obituaries if Pujara comes through over the next year.