I don't think Blade or Deadpool especially need R rated graphic bloody violence to be good adaptations.
So many people demand R rated graphic violence for those kinds of characters though so y'all got it
MoM was surprisingly horrific without being overly gory
If the MCU label wasn't slapped on it, would it really be considered surprising?
Everything I have heard about it suggests that it's not that graphic, especially not compared to some of the movies of that ilk of the 80's. Plus it was directed by Raimi, who has a long history of knowing how to skirt the lines with age ratings. (Sam Raimi is exactly why we changed the age rating system in the UK, after parents complained about Spiderman earning a 15, so they couldn't take their children.)
Meanwhile Blade and Deadpool comics have more extreme violence (And with Deadpool, naughty language and blue humour) baked into the personality of their books.
I'm not going to sit here and say it definitively can't be done, but a Doctor Strange sequel leaning towards the darker side of PG-13 doesn't really suggest anything about whether those characters could have more family friendly movies made about them while remaining fan pleasers.