Considering that Mt. Spokane is Washington's largest state park, it is a little odd that they have so few campsites (eight of them, if I'm remembering correctly), but I certainly don't mind a small campground. For the number, the campsites could be more spread apart, however.
Mt. Spokane is such a wonderful state park though that even my few complaints about the campground is easily overlooked. The trails, views, flora, and wildlife is spectacular here and I'd gladly sleep in the parking lot if that was my only camping option.
I went camping here in early July when Spokane had a heat wave of over 100 degrees temperature everyday, and on Mt. Spokane the temperatures were a good 10 - 15 degrees cooler. With a breeze and lots of drinking water it was well tolerable.
I booked the last available campsite at the campground for our trip as it was last minute, it was definitely the worst of the campsites but it still was not that bad. I'd stay at that same site (site #2, btw) if it was the only one available again. It had a single tree (so no hammock setup for us) which did little to offer any shade, and it was right at the entrance of the campground. It did only have a neighbor on one side though which is nice.
If I went again, ideally I would get campsite 4 or 6. They are both much better than campsite 2 and, in my opinion, the best two campsites at the campground.