Of course Batman is teh bestast evar!!! in this series, considering Morrison's massive boner for Wayne (culminating in lol Batman killing Darkseid with gun)
Wrong. And wrong series as well.
(actually Morrison's favourite superhero is The Flash)
EDIT: Now, I'm going to take a bit of time to explain why White Martians are not acting stupid. First of all, in case you forgot they spent considerable effort into making sure humans just roll over without resistance, first with orbital mind control satellites and then by neutralizing the Justice League. You'd also notice that a single pocket lighter or little fire does NOT rob them of their powers, as demonstrated by Batman. The purpose of the page with everyone lighting a small fire is to show resistance, with the actual big fucking fires being the real bad thing for the Martians. Similarly, how often do you encounter large fires in your daily life?
As for their motive, it's because they're hardline Martian supremacists who wanted to rebuild Earth, Mars' sister planet, in the image of ancient Mars. It also bears mention that without their superheroes Earth is very vulnerable. Especially to a super-species like the Martians.
It also bears mention that the fire weakness was not a new thing, it's been the weakness of Martians in the DCU ever since the introduction of Martian Manhunter, though the history of the weakness and its exact nature is convoluted and I don't understand it entirely so I won't get further into that. Suffice to say that fire does not act like Kryptonite to them, not being toxic or allergic, but simply prevents them from effectively using their powers (as their strength and invulnerability is tied to their molecular control over themselves).
Finally, I will point out that this series was never about deep storytelling, character-driven drama or mind-bending ponderations. It was from the start about reconstruction of the Justice League into its roots, and served as a precursor to the later "widescreen comics" spearheaded by The Authority in making threats and stories larger-than-life and way out there. It's a whole lot of fun and full of energy, biggerstrongerfaster, with witty dialogue and strong characterization, and that's why people love it. Personally I prefer comics like Doom Patrol and The Invisibles, but I can appreciate Justice League (and the various mangas being posted), and it's important to be able to savour all good fiction and not limit yourself.
PS: Grant Morrison says Superman picked that mullet from hell when he died.