The super heavy tank is our answer to:
Lots of medium armored tanks, other super heavy tanks, some really heavy fortification we like to see go and they can be an answer to Titans but shouldn't be.
Also 2-3 per warhost is still likely more than we will build at this point even with the discount, make that more like 1 for the heavy warhosts.
The thing is though, we
can create an option to dealing with medium tanks and other assorted chaff, the Forgehammer design would be an effective MBT for this reason (A vehicle grade starlance - which is three/five times as powerful as a lascannon mounted on an Imperium tank - lets us chew through most armoured threats we have to deal with (hell, the Starcarver is TWO TIMES as powerful as a lascannon, that's bound to seriously threaten most unshielded tanks)
Best to just save the Superheavies for when there's a titan stomping around / heavy fortification that needs demolition.
Starlance vs lascannon is better. Starblade vs starlance is specialized. Better in one particular kind of engagement - vs high end enemy superheavies, worse in all others.
That's only if we throw every system slot we have into giving the tank superheavy weaponry and cannibalize the other weapon slots, which shouldn't be the way to build a SH imo (leaves it anemic otherwise).
Overkill is good but you're acting like it comes with no tradeoffs. The Starlance's RoF means it's a hell of a lot more useful against smaller/more numerous targets, and IMO we're not so flush with either resources or AP that we can choose to make our superheavy tank so specialised.
The thing is though, this isn't really min-maxxing our SH - or at least we SHOULDN'T be gluing an extra SH Starlance onto each tank and gutting the rest of its arsenal to fit it if we can help it, THAT is over-specialising.
For the sake of providing an alternative, I'll be using my plan for a superheavy tank as a visual aide and try to break down each part and why I think it works together.
--[X] Plan: Forgemaster's Tools
-[X] "Vaul's Anvil" Superheavy Grav-Tank (Full Exotic Panoply)
--[X] 1x Starblade (Superheavy Slot)
--[X] 2x Starlance (Vehicle Slot)
--[X] 3x Fatecaster Rifles (Heavy Slot)
--[X] Vehicle Holo-Field,
--[Z] 3x Vehicle Grav-Shield.
--[X] Trade in 2 Ranged Slots -> 1 System Slot.
--[X] Trade in 15 System Slots -> 2 Vehicle Slots + 1 Heavy Slot
--[X] 1x Starcarver (Vehicle Slot)
--[X] 1x Fatesever Cannon (Vehicle Slot)
--[X] (Crew Equipment) Void Guard Armour, Starblaster Rifles + CCW (Hammers)
First up, the Starblade in out SH slot.
This should our big, anti-titan / anti-fortification gun, point it at anything smaller than a warhound titan and it
will die (Flavour text implies that it can shoot THROUGH the titan's shields and still have enough firepower to instantly core it in a single shot)
Granted, it shoots a little slower than an equivalent starlance, but this in comparison to
Starlances which are stated to fire uu
pwards of FIVE TIMES faster than any Imperial equivalent.
Fire rate shouldn't be an issue with the main cannon, and the ability to instantly no-sell most forms of superheavy or titan-related dickery cannot be understated.
But with only one SH, this gives us the option to select MORE weaponry to generalise our titan killer further.
For example, two vehicle grade Starlances.
These are going to be our anti-armour implements for when there's an armored target in front of us (main battle tanks, walkers, dreadnoughts etc), but we don't want to waste a shot from our starblade on them, plenty of fire rate, plenty of damage, a pretty good support to the main cannon in terms of dealing with fortifications (or at least it SHOULD be good for forts) and heavy armour, all in all, a pretty effective secondary weapon for the VAnvil without compromising the efficacy of our main cannon.
3 Heavy Fatecasters are reserved for anti-infantry shredding, not much to really say on these other than that any MEQs or TEQs trying to take on the VA in a straight fight would be shredded piecemeal.
Next up is the vehicle grade Starcarver.
Now this, I admit, is reaching a little, this is primarily an anti-MEQ / TEQ weapon and would seem reasonably out of place on our tank, but here's my explanation why I've picked it:
This may be an anti-infantry weapon, but it's also TWICE as powerful as a lascannon with a LUDICROUS fire rate (Killing entire squads of space marines in seconds) which means that we essentially have a fast-firing laser weapon that can moonlight as an anti-vehicle / anti-fortification weapon in a pinch, might not be its intended role, but for supporting the starlances as a tertiary weapon system, it should do its job well.
Last and not least is the Fatesever.
This is for when an opponent is too slipperly for our other weapons to catch (like with Biel-Tan) and with the ability to almost always hit SOMETHING important thanks to the psy-scopes it won't take many shots before anything we deal with gets destroyed or proverbially nailed to the ground when it hits an engine and promptly glassed by the rest of the armament.
All of this combined should create a pretty healthy SH that can deal with pretty much anything we might encounter from the Orks, (fortifications, titans, superheavies etc) while ALSO giving us the ability to deal with lighter vehicles and infantry, and also dealing with any vehicles that might be as fast / faster than us or is using holo-fields.
And even if all of this DOESN'T work out and it still needs some supporting elements to keep an eye on the VAnvil, the Forgehammers, Chisels and our troops could screen it (and honestly, if any SH gets caught without an escort of infantry / smaller vehicles, that means we screwed up somewhere) and we can still one-shot a warhound thanks to its main cannon.
I admit, this plan isn't as perfect as it can be, the VAnvil could replace its starcarver with an extra fatesever cannon for even more anti-holo-field efficiency and we could sacrifice whatevers left of our system slots to cram in an extra gun or two, but the VAnvil would be a nice generalist alternative to the Anvilsund or any SH that goes all in on the big guns.