it's hard to say anything about 11 slams, or whatever number of majors he will win... we can just guess
I guess he'll stay #1 for a long time, really not sure who can overtake that #1 (Fed is not playing Miami, Murray is too far behind, Nadal is a puzzle with his injuries plus he doesn't seem to care about HC any more) but it's not given ... just too many things involved when we talk about rankings. traditionally, Novak's been very good at IW and Miami. yeah, his chances are good to stay at #1 till October but we'll see ...
As a fan of his, getting into triple digits at weeks at No.1 is fantastic, something I definitely couldn't fathom a few years back. As for Slams, I think he gets one more this year for 7, and even if he averages 1 per year for the following 3 years he can still get to 10, which is realistic and again would be spectacular for him. But you're right these kinds of things are very difficult to predict. So many variables.