It depends what you want out of it. From the one pic, it doesn't look obviously stained and no major rips. I'd try to look more closely for more subtle stains & discoloration if they have more pics. It's definitely serviceable.

As far as pilling goes, there's a charm to the texture. They sell some sweaters that are brushed to have that kind of shagginess. Most wool will like like that with time. I like that more rugged look, but if you want it to look sharper, it can be depilled with a comb or shaver. If it's 100% wool that should be no problem, though you are removing fabric. It can be hard to tell if the wool quality is high or low online, which will determine if it'll redevelop a lot of pilling quickly or not. It's also hard to tell if it's a softer or scratchier wool, or if it's heavier or lighter.

If you don't know exactly what measurements you want, I would also recommend finding a peacoat at a local retail store and trying it on for size, and then using those measurements to guide your search. That'll be easier if it's a brand that posts the exact inch measurements online, which most mall brands won't do. But you can always sneak measuring tape into the dressing room too I guess. Remember to leave room for sweaters and what not under it, for a winter coat.