From my experience, I've noticed the detractors of DC complain about the "grim and gritty" nature of the films. And I honestly don't know how that is a problem.
I am yet to hear someone complain that the MCU is always fun and witty. Every movie has had humour, no matter what the world-ending scenario is. You know what? It's fun, and I like it. We've had 11 movies of that so far.
Why is it, then, when DC has had one movie in it's DCCU take a serious tone (5 if you account for TDK trilogy and Watchmen strictly on the basis of DC output), do we have people complaining of some arbitrary "always" grim and gritty? Complaints that "we're tired" of the grim superhero? The lighter and humour filled superhero movies far outnumber the gritty ones.
I like the variety we have right now. If I want fun and witty, I see the MCU movies. If I want a more serious tone, I go to DC. This seems perfectly acceptable to me.
Ideally, however, we'd see great variety: DC with some fun and witty movies (again, we've only had one movie in the DCCU, so we'll see); and some MCU movies take a more serious and gritty tone.