Sorry, can't help myself
Here's the average age of each clubs 22 (average over all 22 games) from 2012:
1 St Kilda 26.31
2 Sydney 25.94
3 Geelong 25.91
4 Fremantle 25.17
5 Hawthorn 25.06
6 Adelaide 24.98
7 West Coast 24.73
8 Carlton 24.69
9 Bulldogs 24.62
10 Essendon 24.59
11 Brisbane 24.46
12 North Melb 24.4
13 Collingwood 24.25
14 Port Adelaide 24.22
15 Melbourne 24
16 Richmond 23.89
17 Gold Coast 22.72
18 GWS 21.89
So as we can see being older generally means being better. Losing experience and becoming "younger" is not a good thing.
I have no idea about average list ages but they aren't really as relevant because those youngs guys aren't even best 22. There's no guarantee that when they come into the side they will improve it.
10 Essendon 17.59
12 North Melb 17.4
Adjusted for Fletcher and Harvey. Ha we still win