I was gonna suggest Freedom + Ink + CSP. They cover a large portion of category spending and some more (because you can buy giftcards at staples). But since you didn't find UR points useful...hummm let's see...try TYP? But I fear that won't appeal to you either....soooo yeah stick with amex?

If MR points do the job for you then there is no reason for you to pickup SPG. Yeah SPG points might be worth a little more (for now!) but it doesn't give more points on flight, restaurant, gas, and supermarket. But you also need to keep in mind that additional points on restaurant, gas, and supermarket is only limited within US.

If you must pick SPG, get the business version (it also gives lounge axx).

Discover cards are cashback btw. And they are poor for international travel.