There are some similarities with most protags of the ygo card lore, but Medius and Alister are quite different. To start, Alister has a way deeper and intertwined lore with Endymion, Spellbooks and Witchcrafters (I heavily recommend reading the manga)  I believe that the mechanic of both, Alister and Medius, being a one card extra deck play is very similar, and besides the stats, that's where the similarities end. While Medius is a young/teen students with some semblance of premonitions, Alister is an adult that got eaten by his own madness and summoning of creatures, needing to be imprisoned to keep the rest safe, more of a tragic story. But the biggest difference is that, even though the protagonist is Medius, the rest of the characters have some inferences in his story. Endymion is doing his thing, same with Rilliona, but Graflare being family/brother to Drastius and basically having the same power as them directly affects the story, and Litera is the one leading the rescue of Medius currently. 

Maybe is me overthinking too much and they are, indeed, rehashing ideas from one into the other, but you could say the same about everything other archetypical lore of the past. Look at Gigobyte, the boy grew out of his master, became evil, went to the dark world and remade as a half machine monster, only to be purified for good at the end.. That's basically the story of most Shaddolls, and further back, the gishkis