Drake's probably not gonna work too well for a live-action flick. But yeah, much as I dig about half of Giacchino's work a whole lot, getting a little sick of him lately.
Go weirder with this, Batman doesn't need big brassy Silvestri/Giacchino stuff like the Caps & Star Wars/Jurassic Parks of the world.
I dunno, hell, throw a dump-truck full of money Reznor's way maybe. Find a way to get him all p*ssed-off again, Trent in the right headspace could probably deliver a nice mix of the somber piano melodies and the grimey urban-decay industrial stuff, without going full-on cliche millennial dubstep awfulness like most electronic guys would.