As much as we might miss some of the characters who died in Infinity war, this avengers movie was not necessary. The story ended perfectly in last movie. I feel that this was an effort to bring back lost characters for whom most of the little boys and girls cried for in last movie... and in doing so, making tons of mistakes and dynamics change that made it near unwatchable. As much as it upsets people, Thanos was always right. And this was just a sad attempt in making him the unreasonable bad guy... sad.