We learned a lot about Stannis, got a heavy dose of him for someone is no longer a player. His motives and philosophy were just very different than Petyr's and not so interesting. Petyr has been significant since at least he put the knife to Ned's throat. He co-killed Joffrey, Jon Arryn, etc. That's plot enough kind of stuff. That's Petyr's world, being quietly significant.
I absolutely don't want Petyr to die and I will be disappointed if he does. But I absolutely don't see why it's clear he won't die this weekend when you consider Stannis's arc.