MoonDust

As someone who has been a tank commander . . .  Adding another five feet or so of length to any IFV or MBT is something that’s both avoidable and unnecessary.  And would little to no benefit. 
 
There’s a reason most MBTS and IFVs are only so big, regardless of country of origin, and why western MBTs are are all roughly within the same general parameters for size and height.  
 
And adding length also changes up things like mobility, weight goes up, the amount of track you have to work on and runs afoul of design hard limits.  Things like how many you can fit on a HETT, how many a flatcar can carry, etc. 
 
 
EDIT:
 
The IFV/CFV and MBT have different and unique roles on the battlefield.  What works for say Israel’s threats, doctrinal philosophy and broader situation doesn’t readily apply elsewhere.
 
Trying to mix tanks and IFVs/creating an all in one AFV generally means you’ve created something that, instead of working as a combined arms team and being good at one or two things, is just equally shitty at every role it’s trying to fulfill all at once. 

That and carrying the vile peasants, uh, I mean the infantry aboard your glorious beast is just Haram. :p
 

That and carrying the vile peasants, uh, I mean the infantry aboard your glorious beast is just Haram. :p
 

That and carrying the vile peasants, uh, I mean the infantry aboard your glorious beast is just Haram. :p
 

That and carrying the vile peasants, uh, I mean the infantry aboard your glorious beast is just Haram. :p
 

That and carrying the vile peasants, uh, I mean the infantry aboard your glorious beast is just Haram. :p