>>64431768
I'm being a bit pedantic about it, i'm talking battlefield roles not technical specs mostly. I'm also deliberately using the Marder and Nork designs as examples 'the lightest armed IFV and heaviest armed APCs' as most would classify them via firepower.

>the 25mm cannon is superior to twin KPVs in both anti-infantry and anti-armor roles

Anti armor yes, however against infantry in the majority of cases the human body and most cover doesn't really care much if it was 14.5, 20, 23 or 25mm since obliterated is obliterated. Assuming equal amounts of ammo it is correct that bigger is better but that is not the case; smaller rounds mean more ammo. A 323 carries more than twice the rounds as a M2 does and in many situations (urban combat or AA) is superior due to turret elevation: If you can't hit it size is meaningless.

>they are not being deployed without infantry
calling them light tanks is silly when they are acting exactly according to their intended purpose of fighting alongside their dismounts

In many cases that may be true however doctrinally there are many cases where that is clearly not the case; the first gulf war there was very little opportunity to dismount in many of the mobile battles and we have seen many instances of footage from Ukraine where they are unsupported including going head to head with MBTs.

What i am getting at is that the definition should be primarily one of use doctrine instead of technical classification, pic related and a Marder are going to be used in almost exactly the same way besides amphibious operations. Not that use doctrine is entirely accurate either: Does a Merkava stop being a MBT and magically become a IFV the instant you kick a squad section out of the back?

Neither method of classification is satisfactory but i feel use doctrine is the better one. If you disagree than that is fine, i'm not sure myself.