Cobra advantages are:
1. V-hull design for IED protection.
2. Mobility in rough terrain
3. Versatility in carrying different types of weapons, ATGM, SAM etc
If you put a bigger turret on Cobra,
1. its weight will increase and can affect its mobility.
2. That also requires space for a different kind of ammunition inside its storing compartment. smaller calibre gun, more ammunition storage.
3. Cobra mobility can be affected due to recoil of a heavier gun
Cobra can be good against Mines and IED, and retains the scoot ability of a humvee to leave a scene immediately but if it stands its ground, it doesnt have adequate protection against RPG. Add on armour or SLAT armour will increase its weight. For a 190hp engine that might become difficult.
The crew will increase if a heavier turret is put in place. wiki says Crew is 1 +8. 1 means driver, then it must carry 7 passengers? if a turret is placed on top, it may reduce the troop compartment (due to turret space or ammo storage) and crew will be increased to 2 atleast. That means maximum 6 troop carrying capacity or lesser to 4 or 5.
Piranha or LAV III can be equipped with SLAT armor for RPG protection. 25mm is good enough for urban combat. troop carrying capacity is 3+6, almost like Bradley.
I mean different vehicle without personal carriers .
We have Otokar ARMA and FNSS Pars wheeled IFVs have 6-8 men capacity with 25-30mm turrets.
They are huge and big like tank. They weight nearly 20 ton, lenght 7-8 metres, high 2,3m.
Are they compact and smart?
In the central street of east Turkish cities can be used gun carrying vehicle.
Turkish Army in this streets uses M60 tanks!!!!!!!!!!!!!!!!They havent IFV platform vehicled or tracked with 30mm turret.
They havent wheeled IFV with 25mm turret.
First problem in the street wars: Walls and buildings. You need bunker busters, you should open the side of targets.
You dont see where is your enemies. Tanks are used in city but is it smart?
For city fights against terrorism, They need wheeled compact vehicles.
This turrets (In my photoshops) arent huge. BMP1 turret and other 25mm turrets weight maximum 1,5 ton.
BMP 1 uses low velocity gun systems. Low velocity gives less recoill. This turrets are being used on Toyota pickups by terrorists.
This BMP 1 gun shell has great penetration like HEAT ammo but they havent long range. For street fights it isnt problem.
Why we cant stick on Cobra? we can increase Cobra height.
Cobra 1 weight 6 ton, but cobra 2 weight nearly 10 ton.
Cobra was only example, if you want, you would imagine more smart and compact vehicle.
I have imagined only fighting vehicle , not for transporting.
Against RPG bigger tanks( with big armour) can not save themselves.
Please look this Panhard CRAB with 25mm weight max6-7 ton. There is no need personal carrying.
Fox armoured car with 30mm weight max 8t lenght max 5m.
Panhard AML
This turret has 60mm mortar and autogun.
This ERC-90 more useful for city fights.