Well... what about combining that drawback with the idea of rotating benchmarks?
A Game benchmark has (e.g.) 12 months with full points, then when the next big game is released, that takes over and the old benchmark is given less points and with each year, the drop in points continues, to reflect the fact that interest in the benchmark is transient? The (increasingly obsolete) benchmark fades away, instead of being booted out overnight.
It doesn't matter about 10-15 people losing points when the bench is replaced.... no-one complains when a new GPU is released and the same thing happens.
One thing though: Given the "loyalty" of COD and MOH fans, HWB will ideally need benches for each to keep people happy