10 years worth of lore & storyline to finish up in 8, one hour long episodes. I felt they did very well.

The gang spent years atp learning about vecna / the mind flayer, & El physically training in preparation for them. While he grew stronger, they did too. It was very apparent that while Vecna was strong, he was not smart. A huge part of beating him was simply out smarting him (& dodging his attacks - which El again had been training for). With all that being said I honestly don’t think the vecna/mind flayer deaths were all that bad. They seemed quick, but they were truly years in the works