As the name suggests, Mega Evolution's main focus is Mega Evolutions of popular and powerful Pokmon, and very few are more popular than Gen 1's starter Pokmon
While both narrower and less powerful as a Grave Pact Savra does things on her own and offers some utility in the life gain
Things become more questionable in the long ter, and my guess is that collector boosters will end up winning because all of the rare special printings that aren't found in set or draft boosters are more likely to maintain their value than normal printings are
If you're a Pokmon TCG collector, chances are you've experienced the thrill of hunting the most beautiful cards for your binders
Caretaker's Talent can copy any token with the first level gain, not just creatures
Setting up future turns is obviously powerful, but the scry is lost if players crack a fetch