It being a water world (and we call ours an ocean planet) is entirely possible.
Still, this IS a major step to finding a habitable planet, possibly with its own native life forms, or even aliens. Although finding aliens within a hundred years of our tech level (a la star trek for most of their aliens) is extremely slim given the age of the universe.
Hell, I believe they've found a gas giant which is 12 BILLION years old, and three guesses what it's named. So, there could be life that is far, far older than Earth.
Edit: Theres a bit of info thats not in the article, CNN mentioned that the average (I assume) tempurature is 79 degrees. I checked the exoplanet app (I'm sure a few of you guys have it) and it says that the average is 22 degrees C or 71 degrees F. Considering that our planets current average tempurature is around 10-12 degrees C and Earth has been that warm in the past, it's going to be a warm planet.
If it's not a complete water world, it could turn out to be a paradise climatically.
Too bad its 600 light years away. If it were 60 light years away, I guess it would be feaseable to send off a message. Sure it would take 120+ years to wait for a response, but at least we wouldn't have to wait a thousand plus years for the distance it is at. Heck, theres a chance that we would have developed FTL drives and gotten there before the message arrives.
We should start taking a look at our closest neighbors within 100 light years.....