Re-read the chapter for the 4th time or so.... The panel where Madara says, "He's....Too Strong..." referring to Gai. I guess that if Madara in his suped-up state says anything other than "You're no match for me!" then it must mean that Gai is about to become top 10 material. Although I have to agree with the other commenter that the "Top 10 has gotten VERY crowded" over the past year! Gai has moved ahead of Kakashi...
Here's a brain scratcher for you tho... Where does Madara know Gai from? The chapter before this one, when Madara sees Gai, he seems to recognize him. My theory is that a loooooong time ago there was a teacher of Taijutsu that looked ALOT like Gai. Maybe even wore a similar outfit and sported the same super cool bowl cut! Madara recognized him as the protege of the ultimate all-time Taijutsu master or maybe even a descendant. There's gotta be something to it though because of the time frame of when "old Madara" died, Gai would have still been a kid and wouldn't have attracted Madara's attention. So where else would he have recognized him from?
btw...thanks for posting this thread! Been interesting to think about...