By the time those game come out, Gamepass will be so expensive you'll spend more than 70$ to beat them all. It seems like a good deal now because we all did the GPU conversion trick but then what? I barely use my GPU for the same reasons that poster said. The MS exclusives that are actually on the service right now are bargain bins fodder you could just buy outright and save money. 3rd parties I already have or they leave the service before I'm done.
Besides, Demons Souls is totally worth 70$ and you can easily sell it back for 50$ right now. I never pay full price for my games anyway (preorder bonus, trades etc) but I was always able to recoup some of my money with Sony games up to 3-4 months after release. Their games are so good it's 20-30$ well spent to me.
Why are you using Gamepass for only exclusives?
I use it for day 1 releases and games I was interested in that I was waiting for a sale on.