Based on the rough translation available on this latest DREAM.16 promo, it seems like they're talking about the possibility of Jason "Mayhem" Miller being Sakuraba's "successor". Mayhem also said that he plans to be the first guy to submit the legend:

"I've worked my whole life to make my style the same as Sakuraba's. I think I maybe I can be the first man to submit Sakuraba. I think I have the skills, and I hope to prove it"

I may be nitpicking, but even if Miller pulls it off, he won't be the first to submit "The Gracie Hunter". Technically, Kimo Leopoldo was the first guy to submit Sakuraba on his MMA debut way back in 1996... Well now that we have that tiny detail out of the way, the more important thing to ask here is that, can Mayhem Miller fill his shoes and be the next Sakuraba? and will beating the 41-year-old MMA legend be a step towards that? Probably not.