Wait so most of the planets I find are going to be floating rocks?
How much variation do you think we'll be seeing here?
A lot. You guys do know that not all planets can support life, but of course, sci-fi blah blah.
If you think about it, there would only be two or one or zero planets in each solar system you discover that will be able to support life. Of course, you may not think about it so much, but those who do not look like it might just be able to have bacteria in the caves you go in. Who knows? Maybe Hello Games will just break that rule and put super cool aliens on the moons of gas giants or something.
If you go towards the center of the galaxy, stuff simply gets more odd and angrier and alien. So no, probably not floating rocks, because the only floating-rock-of-a-planet is Mercury, who is doused with radiation and heat. There was a mentioning that there is also poisonous planets, planets like Venus, that you need to upgrade your suit in order to be able to survive in them.