Well, I think it will be more than 1000, my estimate is 1200-1500.
Anyway, out of them 80% will quit after first difficulity with installing, other 10% when they find out there is no STL in U++ and other 5% because of documentation.
It would be a huge success to gain 2-3 new U++ programmers from this release.
But, as you have said, Rome was not build in a single day....