Pycelle isn't using magic (or very little) and doesn't have a full grasp of how to do it, however he does know how to make them stronger.
That wasn't Pycelle. That was Qyburn, aka the Half-Maester. He was tossed out of the Citadel before he completed his chain for his early study of Necromancy.
Ramsay has screwed up, big time. He cited the Karstarks, Umbers and Manderlys in his corner.
Umm - young Lord Karstark is still pissed that Robb beheaded his dad, but the Karstarks and the Starks are cousins and go back thousands of years. They are a splinter off the original Stark lineage.
The Umbers are Stark supporters. The Manderlys hate the Boltons. The Tullys already hated him.
And now Ramsay has probably pissed off Walder Frey, and Peter Baelish would push the Vale behind Sansa too. Finally, if word gets out that he killed Roose, the Boltons will turn on Ramsay too. He is literally the most despised man in the North. Dumb, dumb play.
He is gonna get his.
Similar situation for Cersei. I think that she is gonna get revenge in KL, but Dorne (not just Ellaria and the awful Sand Snakes, the whole damn army) is gonna show up and deliver a knockout blow to the Lannisters. The only question there is which side the Tyrells take. They historically hate the Martells/Dorne, but they are currently pissed at Cersei.
Short version: there's gonna be a reckonin'.
Also, I think Melisandre is gonna rediscover her faith in her new Azor Ahai - Jon Snow.