I have to agree to a degree. Devs are shoehorning this open world structure into games that don't benefit from it and actually it becomes a nuisance.
For example Batman games could just do well to let us just play the missions in order without flying for 10 minutes around the map between levels. While flying around there are so many useless distractions and side missions which are all boring. You know they put them in there to waste your time. To stretch out the real content.
The new Tomb Raider was a welcome departure from this open world concept. Finish a level and the next one is ready to play. Even though it has filler material you can ignore all of it and just play through the story.
I've played a couple of the Batman games, and while they had side quests, they were completely optional, with plenty in the main story to keep you busy for quite some time. The problem is that some times we need to make a choice to ignore the side quests. Although I found doing the side quests great, as they gave me a chance to practice new skills. They also had a ton of challenges, which were also pretty fun, but optional.
I do get that the open world sandbox style is becoming overly used, but as gamers, we do have a lot of control over what we experience. We have to train ourselves to focus on the goal of having fun, and if that means ignoring side quests, do so. In fact I personally tend to ignore side quests on my first run through in all these sandbox games, and use the side quests as a way to add replay value.