A year ago I figured something like 10-12.
I guess he may get 13 total, not too bad.
He can always lose at RG even, so that has to be taken into account.
Remember how long it took for the first 6 majors, a long time.
He had 6 majors at the age of 22 before his prime..........how long did Roger took for his first 6?
BTW, Nadal has 9/26 record at the SLams....only surpassed by Borg percetange wise with 11/28. Not too shabby!
How many players have 5 straight slams, and on 2 surfaces?
Remember that Nadal couldn't continue his RG streak to 5 in a row.
Even now with how well Nadal is playing he gets knocked out of tournaments early.
I don't even know if he can accomplish a less than double digits defeats for the year.
He never made all the finals of majors in one year, this shows dominance.
I could go on for pages, better to compare Nadal to the second tier players for now. 
A better guage would be performance starting with the first slam, this is when a player comes into his best play.
How many players have won 2 slams in three surfaces?
How many players have won RG-SW19-UO in one year?
How many players have won RG-SW19-UO in three different surfaces back to back to back?
How many players have won the Golden Slam?
How many player have won the Career Slam by age 24?
How many players have one 81 consecutive matches in one surface?
How many players have won the Clay Slam? (MC-Rome-Madrid-RG)
How many players have won two or more Channel Slams?
How many players have won 18 MS shields?
How many players have won 5 consecutive titles over three surfaces?
How many players have won 3 DC for their Country?
Who was the first player to hold three slams in three surfaces?
I mean, we can play this game all day..........Roger's record are sublime, it doesn't mean Rafa doesn't hold his own share of records....your tier 2 comment was amusing at best.