>>pg+e
This makes the assumption that 'senior' members' voting habits haven't degraded over time. Say a bad post hits the front page - would this subtly influence future votes (regardless of how old someone's account is), resulting in more bad posts making the front page?
On a semi-related note, it would be neat to keep a history of the front page at regularly sampled intervals (say every year, starting at year 1) and see how the two measurements diverge over time.