If he was alive today...

People are products of their culture, so if he was gen X then yes.

Perhaps a better question is this, if the classic Psycho was just released today as is, would it be a hit or would it be too dull for today's over the top horror movies?

I think they would be full of proper English, if he were alive today. He would also concoct an original username, My Cunt.

I think he would've approached violence very much in the same way as how movies such as Se7en and American Psycho did. Both films have reputations for being rather graphic in their depictions of murder amongst casual moviegoing audiences, but if you actually look at how those movies were shot, they actually don't show nearly as much blood as one may have initially thought. What those films did, however, was show just enough for audiences to get the clear picture of what the filmmaker's trying to illustrate, while still leaving a fair bit to the imagination so as to avoid the label of torture porn, which isn't at all unlike what Alfred did in his films (most notably with the shower scene in Psycho). What those films did, was simply take Hitchcock's methods to the next level, by implying violent acts with even more vivid detail, while still leaving the real nasty stuff out for our minds to fill in the blanks.

In regards to sex and nudity, though, I do think Hitchcock would've likely showed a lot more. Given Hitchcock's reputation for being somewhat obsessive towards his leading ladies, I think he definitely would've filmed his fair share of graphic sex scenes if given the chance. What he'd likely also do, however, is use those sex scenes as a way of exploring the psychology and feelings of his characters, rather than just film something graphic just to placate to his perverted desires. The sex scenes in films such as Basic Instinct and Lust, Caution are probably how he would've likely directed his sex scenes, with graphic detail and no-holds barred nudity, but also a fair bit of psychology and subtext involved. Titillating, but artistic at the same time.

Aside from sex and violence, another departure Hitchcock would've likely made in comparison to his earlier works, would probably be in his endings. Because of the studio system Hitchcock worked in back in the day, he was forced to often create happy, clean cut endings when he himself would've often preferred darker, more ambiguous endings. Had if Hitchcock was still alive and making movies to this day, I think he likely would've had less and less happy endings in his films as time went on.

If Hitch were still making films today, they would likely be pretty raunchy.
Graphic movies are pretty much standard these days.