Personally I think the ideal squad is 17 senior pros who should all be capable of pushing for a starting spot depending on form and fitness and 3 youngsters introduced over time.
Our current squad had far too few players outside the playing XI putting pressure on the starters.
The salary cap limits the ability to do this, I cant think of any A-League clubs that have 17 players all worthy of a starting spot.
Assuming that the 3 youth players are all on just 70k a year, there is $2,290,000 available in the cap. That gives an average wage of $135,000 for each of the 17 players. Players like Ifill and Stein are obviously going to be getting paid a lot more than that, so other players will have lower wages as a result.
I agree that having a squad like this would be idea, but it'll be rather difficult to find these 17 "senior pro's" you speak of when we can only offer some of them less than $100k a season.