I think the government should fade out all the other suburban sets and only have A-sets, and also design a V-set replacement and replace the V-sets.
-V Set repalcement should be done in next 10 - 20 years when the last of the Vs cannot move.
-Suburban sets will not be repalced with A Sets due to the many issues with getting supply back and stuff.
-However I do see maybe OSCars doing Suburban duties once the V Set repalcement comes (if they order enough to repalce all the V Sets and OSCars) and possibly new trains to replace the remaining S Sets (no aircon) and possibly C Sets (bad reliability).
-K Sets will stay until they cannot move s they have aircon.
-Tangaras have aircon and the only issue seems to be computer upgrades which can be done and is possibly being done now or in the future.
-Millenniums are new trains and will not be replaced for a long long time.
The money will be better spend on network upgrades to improve efficiency, on time running and reliability