Except you have more than 3 midfielders Morgan and you can certainly have more than 3 inside mids when most of them can go outside too. In fact about half a side are midfielders these days with smalls at either end getting mid time as well, Barlow definitely had a spot to play amongst those.
Just from Corporal's suggestions, some of those other teams had the following as almost pure inside mids:
Sydney - Kennedy, Hanneberry, Parker, Jack, TMitchell as well as a number of kids who were great inside like Heeney and Hewett
Hawthorn - SMitchell, Hodge, Lewis, Burgoyne and Shiels
There's plenty of room for Barlow, getting nothing for him was stupid too.