The problem with having things how it was before as a fun mixed place for all ages is that it was that way and it died. A slow and painful death. I watched it for awhile, and then left because the whole dying thing was taking too long. The reason the creation of two separate demographics is being proposed is because the old way seemingly didn't work anymore.
I think Draper makes a good point, which seems to have been overlooked, that in the active days when he was a member, 17 was the higher end of the population. So, actually, this sort of older demographic is reflective of the current, older state of BOL, and not really the board in its peak.
I also think Eric's argument regarding young adult vs. youth groups is very valid.