The only battlefield a legged combat vehicle would have an advantage over wheeled or treaded competitors is a heavily fortified battlefield.
Design parameters of a vehicle that has to fight fortifications heavily favor firepower, armor, and terrain passability which all play into the favor of legs.
A legged combat vehicle would have it's primary weapon placed in a fixed mount like the S-Tank because it reduces space requirements which allows for larger weapons and simpler geometry of design.
Fixed weapon mounts have simpler geometry which is easier to armor than a turret or even casemate, Additionally multiple legs gives redundancy to mobility and aiming a fixed weapon unlike the S-Tank.
Legs may have a limited top speed which can only be partly negated by wheels on the feet for on road travel, But having to fight through very rough or forfeited terrain maximises the mobility advantage legs have.
Basically the walking assault gun of the future would look a combination of the T28/T95, S-Tank, and John Dur Walking Tractor.
Ultimately though, No nation at this time has the political reason or wherewithal to develop or breach modern fortifications.
No fortifications no walking combat vehicles.
>>34922802
>John Dur
>>34922802
What about space?
>>34922802
I can see walking assault guns being used in future combat on low-gravity planetoid. There is a certain tactical gain in having a big cannon able jumpjet up from a crater/dune, take a shot then be down again before anyone can return fire.
I'm thinking resource-centered brush wars between corporations outside Earth control, on planetoids ripe with valuable elements worth mustering a company of men and a few mechs to slug it out over it.