Although I can appreciate the problem with having TI as the only criteria for Cpl, this whole issue has been around since before unification. In ‘Dam*‘ the torpedos‘, Paul Hellyer (defence minister) had to reconcile the needs of the army with the air force. The latter could make technicians Cpls with no leadership training, wheras in the army a demanding leadership course was required. It was decided to ‘inflate‘ army privates to Cpls to bring the two in line.
Of course it has never really worked out as advertised. The different technical and leadership skills can‘t be bridged.
Our military of 52,000 can‘t afford completely separate army, navy and airforce, but this is one issue that needs to be revisited.