There is great merit in recognizing the contributions of the most active members as it make the community thrive and encourages more participation.
In that setting it is perhaps important to consider whether the labels used are optimally supportive of that laudable goal.
I believe the labels in use at present may bias the rate at which members respond and post.
Who would be anxious to become a "Senior" citizen in a community? Surely it is already problematic enough to be publicly seen as "Regular."
Why not instill a sense of adventure and excitement by using labels such as "Explorer", " Maestro (a)", "Senator" [recalling the original wonderful FORUM], "Astronaut" etc.
Other approaches might focus on characters from mythology, fabulous creatures, etc.