In the absence of major changes to the legislation regarding Reserve service I'm not sure what this achieves.
Currently 1 CMBG has the following 100% Reg Force combat elements supposedly available to deploy without calling up the Reserves (individual augmentation requirements conveniently ingnored

).
1 x Armoured Regiment (2 x Tank Squadrons and 1 x Armoured Recce Squadron)
2 x LAV Infantry Battalions (3 x LAV Infantry Companies each)
1 x Light Infantry Battalion (3 x Light Infantry Companies)
1 x Artillery Regiment (2 x M777 Batteries)
Total: 2 x Tank Squadrons (38 Leopards)
1 x Armoured Recce Squadron
6 x LAV Infantry Companies
3 x Light Infantry Companies
2 x Artillery Batteries
Under your proposes system, without mobilizing Reserve units we'd have:
1 x Combined Arms Battalion (LdSH with 1 x Tank Squadron and 2 x LAV Infantry Companies)
In total, with full mobilization of the Reserves to fill out 1 ABCT and the Light Brigade we'd have:
Total: 4 x Tank Squadrons (60 tanks)
2 x Armoured Recce Squadrons
6 x LAV Infantry Companies
6 x Light Infantry Companies
3 x Artillery Batteries
So with your system at full mobilization you are gaining the following over the existing all Reg Force units:
22 x Tanks (however if LdSH were to go with all 3 x tank squadrons the gain in tank numbers would be only 3 tanks)
1 x Armoured Recce Squadron
0 x LAV Infantry Companies (In the existing system all 6 x LAV Companies are Reg Force. In your system it's 3 x Reg Force and 3 x Reserves)
3 x Light Infantry Companies
1 x Artillery Battery (no accounting in your system for where the extra guns come from)