Surely it's up to the individual, the availability of certain numbers, and the prevailing attitude from coaching staff?
I can remember players being coy about claiming Robert Flower's #2 until Steven Tingay came along and leapt at the chance to wear it.
If you have a past champion (e.g. #5 at Geelong) what do you do - leave the number vacant because it has a formidable history? While I'd love to see a player strike out and claim the #99 (as I've said in an earlier post) it's a conservative culture with valuable traditions (tradition is just about all we've got apart from a promising young list).
To take up your point though, there's a challenge around certain numbers such as #26 and #37 which are yet to become legendary, while others, such as #3 and #27 have a rich recent history.
The #13 was a strange one until Allen Jakovich, and then Adem Yze made it a blue-chip number. I'd love to see somebody adding to this (growing) tradition. Why not Blease or, even better, Jurrah?
From memory, our list of high number legends/cult favourites is pretty short - #41 Peter Rohde, #42 Peter Walsh, #43 Guy Rigoni, #45 Mathew Whelan (can't think of any others).