Wow...you sure like R Rated movies. Haha. Don't get your hopes up for a similar take on Star Wars. Most of the R elements in Game of Thrones are because that's the way George R. Martin wrote them. But who knows, maybe you'll get your wish. If it serves the plot I might be okay with that decision, but if it's just for shock value I'd rather they stay PG-13.
I can live with them aiming for PG-13, same as the other 4 Disney era Star Wars movies so far, but it would be nice to see an actual adult oriented Star Wars series for once, without anything aimed at kids, be it Porgs, Jar Jar, or Ewoks. The fact that the leaker specifically says that Disney wants to expand the universe and win over fans of Game of Thrones does seem to suggest that Disney wants this to be a mature movie, as Game of Thrones is about as mature as you can get, nudity galore, rape, graphic violence, language, it has it all. I doubt that Disney would ever be willing to go the same extremes as Game of Thrones in terms of sexual content, as that would get them an NC-17 rating instead of an R rating probably, but I could see them aiming for GoT levels of violence, afterall, the wars between the Old Republic and the Sith Empire were some of the deadliest in Star Wars history. The acts of evil perpetrated by the Sith in the current Star Wars movies are nothing by comparison, as there was pretty much only 2 Sith at any time due to the rule of 2, but that ruledidn't exist in the Old Republic era, there were thousands of Sith in the Sith Empire, leading hundreds of thousands of Sith Troopers.