I'm actually ok with Max surviving that first encounter. It sets up what Vecna is and what Vecna is doing, and without it they'd need some sort of crazy way to explain exactly what the hell is going on to the rest of the Hawkins crew.
It is that final encounter where Vecna basically wins and kills Max. Bones broken, eyes blinded, can't feel anything at all and we see "holy shit Vecna was right. Vecna won" and then 11 pulls Jesus powers out of her ass and no, Max is actually only in a coma! She's ok! She'll be back in the next season flying a helicopter and swinging a sword in some side story you care half as much about as the main plot! That I hated.
The basketball bully getting torn in half just so they could resolve that storyline and ensure he wouldn't be around to whip the town up in a fury against Lucas who he saw with Max is just icing on top of the cake.
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Moops? "I thought you were making up diseases? That's spontaneous dental hydroplosion."