Devil's Advocate Part 2
Generalization is bad people. There are many art styles in modern mainstream comics, don't close yourself to amazing artists such as Daniel Warren Johnson (Mid) who is a double threat writer/artist doing both mainstream and indie stuff.
The second issue I see a lot of you repeat is the over-abundance of action and lack of character development. That couldn't be further of the truth. In the 80's Comics used to be one-shots, until having multi-part stories became the norm, giving character waaaay more space to develop and evolve.
Third issue I concede. Mainstream Superhero Comics have the never ending problem of reset status quos and ignoring what the previous writer workd hard on, but you can take storylines as their own thing. For example recently there was an amazing Hulk run, introspective, exploring the character and its mythology, with amazing art and superb horror leanings. When it ended a new artist and writer duo picked Hulk up and changed everything. I personally don't like it as much, but the reinvention on each run keeps stuff fresh.
The haunting Immortal Hulk
Ensemble casts are a long tradition in comic books and has been done perfectly many times over. The problem is the sheer quantity obscure quality. Justice League International is an amazing book from the late 80's and early 90's with hyper-expressive faces and comedy, as it was less of a superhero book and more about what Superheroes did outside their adventures. If you want something more recent Wolverine and the X-men which has Wolverine taking over as the headmaster of Xavier's School (Rebranded Jean Grey's School) is also great with a lot of character interaction.
The current X-men run is less a superhero book and a study in nation building, as all mutants, good, bad, neutral and more, have teamed up under a single banner forming their own nation. It has a little bit of everything, political thriller elements, mysteries, culture building as the mutants generate their new society (X-men by Jonathan Hickman). They became more focused on their own survival than being actual superheroes.
Giffen and DeMateis Justice League International.
Imagine the balancing act of having Magneto, Apocalypse and Professor X assist to a diplomatic conference.
Still, comic books aren't perfect and many issues don't have a counter-argument and could be improved, like better representation, even more variety of art.
Some problems are intrinsic with the medium, as the baton pass of writers and artist shifting a character.
Is a dying industry struggling from air as it sinks. It makes a lot of mistakes.