No dramatic need, no. None whatsoever.
However, think back to the week in early May 2009 when Star Trek opened in general release. Think of all of the interviews conducted during that week with Abrams / Orci / Kurtzman that we saw and read and discussed and dissected.
Now -- in how many of that endless parade did the interviewer not ask some form of the question: "Okay, so you're doing Khan next, right?"
Not many at all. And Paramount, watching over the media response to their new movie, very definitely noticed this.
That is the primary reason we got Khan, even though he appeared nowhere in the early versions of the script prepared for the second (follow-up) film. Paramount insisted he had to be in there, so in he went.
Even if the question of Khan hadn't come up in nearly every interview / review for the first film, the insistence in discussions on fan sites like this one that Khan had to be next was still a big thing. You can bet Paramount was well aware of this, too.
We were always going to get Khan, regardless of whether you or I happened to feel he was necessary or even desirable. Khan was inevitable -- not because there was any dramatic need for him, but because too many non-dramatic factors refused to allow him to not be there. That writing was on the wall in May 2009, in language everyone could read.
This is a great perspective on the matter. It's been almost a decade of hindsight that allowed us to easily say Khan's addition was forced and unwelcome. Putting myself mentally back in 2010, I think I would've found the idea intriguing. XI wasn't a bad film, it had honored the franchise quite well - there was no reason to believe they'd butcher Khan or that it was a doomed idea from the start.