Well that's great that the population went up by a few thousand people. I really don't think that tells the whole story though. People are moving to Peterborough because its a cheap place to live. I lived in Peterborough for four years. Trent and in the south end, Fleming, are really the only things the city has going for it right now (well, and maybe hockey). And the thing is, they may be attracting students, but the students aren't staying after they're done their 4 years, unlike what we see in other university towns. There's no reason to stay unless you score something with the MNR.
It's an old factory town that hasn't found a way to make the transition. It suffers from geography and really only acts as a hub for the surrounding smaller towns like Lakefield, Douro, Omemee, and even Lindsay. Other than Professors and maybe the odd GM worker, I don't think there are enough people travelling between Peterborough and toronto everyday. Maybe you get a weekend surge of students heading back home, but that's about it. It's basically a self-sustaining community where people work, shop, and live without having to leave.
Downtown Peterborough is great. I agree George and Water are in good condition for a few blocks, but take two steps off of these roads and you're likely to find out why Peterborough is often considered the homeless capital of Canada and why Anti-poverty groups have such a loud voice in the city. Racism and Homophobia are prevalent, and it's fairly easy to spot drug deals. I grew up in Welland, which is one of the poorer cities in the province, and there are some parts of Peterborough that make Welland look like Oakville.
Would a go station improve things? Maybe it would attract people looking for cheap land to build big homes on, and who don't mind 2 hour commutes, but I'm skeptical that even that would happen when there are much better choices out there.