If you've never replaced hoses on a '07, then I think it's a good preventative step. I try to replace hoses on my cars around 90k. If you are replacing the radiator, then it makes even more sense, as the old hoses will be a pain to install back. As for the thermostat, I did it too on the CX-9, but kept it on my Subaru for 240k problem-free miles. But once you remove that engine hose, there are only 3 screws that separate you from that thermostat, so why not?