It is not a design, it’s a change allowing the design to work better,
1) Small timed buffs don’t work, as has been gracefully demonstrated by the Command Tiger. Passive short range buffs reward positioning and preservation.
2) Having better vetting will allow it to be more cost efficient and beneficial as a command unit,
3) The aura is the entire point of it being a command unit.
The problem with C.Tiger's aura is not that it is a "Small timed buff" but that it cripples the DPS of the C. Tiger itself, which is probably the main source of damage in one's army composition. In other words it does not actually improve the damage army dishes out...
Imo the aura of the Panther should be separate into:
Always on that could be the vet 1 bonuses
vet 1 active ability timed aura the vet providing the vet 2 bonuses
vet 2 a bonus in the aura it self like lower cost or longer duration or sorter CD
The rest of the vet bonuses can remain but affect the "ability"
or/and one could have the aura first affect infatry and then vehicles...
That would it allot easier to balance the aura and thus the unit.