No. MM3 introduced the slide. MM4 introduced a charge shot. The slide completely benefited the gameplay and made Mega more mobile, leading to better platforming, action, and particularly boss fights. For this reason, 3 is the best nes Mega Man title. The charge shot was like the spin dash in Sonic 2: an extra power move that didn't really improve the gameplay in any way, that the game creators thought would be a good way to "spice" the game up, when they didn't have anything remotely creative to add to its gameplay formula. That said, I haven't played Arkham Knight - obviously - but damn, if the parallels aren't there:
flying in Batman AC : slide in Mega Man :: bat mobile despite the fact the crux of past Arkham's was personal exploration : charge shot in Mega Man.