BTW i voted "maybe", but just because i think it's really difficult to keep this same level during many years, that being said if he plays...let's say 4 more years? (28 years old), doesn't play the Davis Cup ever again, and makes a good tournament schedule then he could get an average of 2 slams per year reaching the 17 titles, not improbable
I know there're many factors that might influence...like injuries again, the arrival of a new king of tennis, his motivation for the game, a full recovered Del Po winning everything....
Another important thing to think about is how is gonna play Federer in the years to come??, and if he's gonna be able to add more slams.