A very good point by Supcon that I hadn't thought of. Yes it means that clubs at the higher levels, Prem & Championship, are carrying squads of 24/25 or more with at least two players for every position.
This leads as Supcon has highlighted, to a concentration of players at some 44 clubs. Whereas if a club only had 2 keepers, 3 full backs, 3 central defenders, 6 midfielders and three strikers plus a couple of utility play anywhere types, we would be back to the sort of squad that Alan Dicks had to get us to the First Division.
That season only 17 players were used by City and two of them, Steve (?) Harding two starts, Brian McNeil 2 sub appearances and John Emanuel 3 starts and one sub.
Thus promotion was won by a squad of only 14 players for 42 leagues matches!
But to get back to the original question; 5 subs or 7? I have changed my mind to 5 only but perhaps the overall question should be whether to have a cap on the number of players registered for any club.
If this took effect how many should it be? And perhaps clubs should also only be allowed to borrow players to cover medically confirmed long term injuries or if one of the two keepers is injured. Or scrap the loan system and force clubs to play their under 18 or 21 Academy members! Or is that too radical?