EDIT: RTFAing, Google even mentions using longer runtimes:
> As shown in the table, the crashes were reported in three iterations: the first one obviously contained the bulk of the issues, as the fuzzer was hitting a lot of different states and code paths right from the start. The second and third iterations were run for a longer time, in order to shake out any crashes which might have been masked by other, more frequently hitting bugchecks.
EDIT x2: Also, it looks like they moved it out of the Kernel in Windows 10, so that's good.
> It's also worth noting that while the elevation of privileges scenario is mitigated in Windows 10 by the architectural shift to performing font rasterization in a user-mode process with restricted privileges, an RCE in the context of that process is still a viable option (although much more limited than directly compromising the ring-0 security context).