What about the second strike? D-Air can't have that much range in front of him, now can it?
Googling about t' search for Roy data. Found nothin'; not that I was surprised... but I did discover that disrespect for modding (and thus, P:M) is a not-so-rare mindset amongst dumb ol' console gamers. da fuq?
Speakin' of, my untrained eye thinks that Roy is more geared to extended combos than Marth, as well as an aerial game in particular. D-tilt is a launcher rather than a raw spacing tool (but still useful for edgeguards 'cause D-tilt -> F-smash). N-air doesn't seem t' have as much knockback as Marths' N-air. Sourspot aerials and U-tilt look like they link really well together at high percents.
That, and Roy has better (consistent) finishers. U-smash and D-smash look more powerful than Marth's non-tippered counterparts. B-air clearly packs more punch. Blazer seems capable of Star KOs at high percentages. Flare Blade is clearly far more potent than Shield Breaker since it lacks said shield-breakin' capabilities... or so one would assume.
If Roy can indeed string together combos more efficiently and has more consistent, powerful finishers than Marth, I would imagine that'd be the case.
... Although since Roy has (most of?) Marth's range, it's safe to assume that his spacing and punishing game will also be quite potent. The only difference is that Roy's tipper F-smash won't be the ultimate punish. Gotta get in there 'n grab or D-tilt.