Miller has written some great comics but is not the huge influence he is taken for.
Dark Knight Strikes Again SUCKED. Let's hope this new one is better. IMHO, been a long time since Frank Miller wrote anything really good. I do love his Daredevil and his 1st Dark Knight. But I am hard pressed to name anything else of his that is even readable. Sin City was a fun movie, but a crappy comic. And I thought 300 was crappy (and historically inaccurate) both as a comic and a flick. He didn't even write my favorite Batman. Alan Moore did (Killing Joke). And though he is still uncredited, the Daredevil tv show owes as much to Wally "Kid Daredevil" Wood as it does to Frank Miller. And note Miller is no more prominent in those credits than Brian Michael Bendis, the Romita's, and others.
Miller has been replaced by Joe Kelly, Bendis, Gail Simone, and Mark Millar as the most omnipresent and influential writers, who in fact have more cultural influence than Frank at this point (not to mention Chris Claremont, who always has had more influence, and that Claremont wrote numerous comics people think Frank Miller wrote, like the original Wolverine mini-series, which Miller did some of the art for and no writing but is still often called the 'Miller Wolverine').
Bendis especially - he is as prominently cited in the Daredevil credits as Miller, wrote DD longer, not to mention he created Jessica Jones and Powers, wrote Luke Cage, Iron Fist, both the standard Avengers and New Avengers, created Ultimate Marvel with Mark Millar, and wrote the Avengers Civil War tie-ins; Mark Millar wrote the main Civil War comics, a bunch of Captain America, and about half of Ultimate Marvel, which the movies draw on heavily. While Kelly wrote the definitive Deadpool run (which is what the movie is based on), and as founder of Man of Action, is responsible for just about all of the Marvel animation of the last decade, wrote X-men, plus over at DC Justice League of America, which is coming to film and possibly tv. Gail Simone has now written more Bat-family comics than Frank Miller (mostly Bar-girl) and is in my opinion head and shoulders above Miller (she also wrote some of my favorite Deadpool and all of Agent X, so I'm biased).
And then there's Jim Starlin, creator of Thanos, Gamora, Drax, the Infinity Gauntlet, and primary author of Captain Marvel and Adam Warlock for over a decade (both due to appear in the MCU) as well as long-time writer of Iron Man. Plus he has an author-owned character, Dreadstar, in development for TV.
Frank Miller was as good as all of these folks once (and is from my neck of the woods in MD). But the difference is they are still writing hugely popular, well-written, influential comics and graphic novels. Even Starlin, who is older than Miller and has been doing it longer. Starlin has a new Thanos coming in June, the Infinity Relativity. And despite having written at least 8 previous massive Thanos storylines over 30+ years, none of them suck like Dark Knight Strikes Again or Holy Terror.