I would argue that for most programmers and applications, significant-multicore does not present a significant advantage or potential over standard multithreaded development. Most people have threads to accomplish sequential jobs, and there isn't that much potential for splitting up those threads to much smaller units.
IMHO, most benefits of significant-multicore would come from improvements to underlying frameworks (e.g., database access, IO, GUI and 3D toolkits, etc.), and the vast majority of developers would benefit transparently.
In addition, future static analysis tools may be able to recommend pieces that could be split further into threads.
