Again BI, you just don't get it.
OK, so people who wrote rules for other game systems or wrote fiction thought that it would be thematic to say 'lance'. Sure, it's more thematic than saying 'Weapon Battery'. However, when they wrote those rules or that fiction, did they know that a lance was an anti-ship gun in BFG? Were they directly saying that Marines have anti-ship capabilities? Or is it more likely that they just wanted something that represents 'accurate' for their bombardment? If it's the latter, and all they're really saying is 'accurate bombardment' then Weapon Batteries can do that just as well. From the description of the Sword class frigate we can see that lasers are used as weapon batteries. This is far more representative of the "lance" rules used in orbital bombardments. After all, there is still a chance of survival in those game systems even when a 'hit' is scored. A bit unlikely if it were a real lance when a lance can vaporise 24 Mantas in a single shot!
What you are doing is using orbital bombardment rules from other game systems to justify anti-ship weaponry in BFG due to a fluke of nomenclature! Hypothetically speaking (you know, pretend), if lances in BFG were renamed something else, such as Space Squirrels, then there would be no case to put forward. "Well SMs are described as having lances in Epic so should get Space Squirrels in BFG". See, it doesn't work. What this tells us is that you have no argument beyond the name of the weapon for SMs to get anti-ship weaponry. Nor is there one.
The "SMs have lances as shown by these orbital strike rules" argument goes directly contrary to the "IN don't want SMs to have lances" argument. You have fluff supporting your stance, we have fluff supporting ours. Ours trumps yours. I'll list why:
1. - General background of the game prohibits SMs from having warships, lances are purely anti-ship weapons, therefore any ship with them is a warship, therefore SMs can't have them.
2. - Specific fluff mentioning that the IN really don't like the SM having the Nova (because of lance)
3. - Specific fluff mentioning that the IN don't mind SM escort sized warships (combined with their acceptance of the Gladius means Nova controversial due to lance armament).
Your fluff does not mention anti-ship capability, nor is it BFG specific. Therefore when reconciling these two incongruencies you have to come down in favour of the BFG specific fluff.
I put it to you that the authors of the orbital strike rules are either unaware of the role of lances in BFG or are unaware of what the consequences would be to SMs having anti-ship weaponry.
If in BFG a lance represented a weapon capable of incinerating whole battlefleets then your argument would suggest that SMs should get them despite them clearly not having this capability. This is because your fluff only talks about lances as an orbital bombardment, and not what they represent in BFG. If you want to have SMs with lances then you'd have to redefine what a lance does in BFG. You're arguing nomenclature. Not role. Not demonstrable fleet engagement capability. Nomenclature. This is a piss poor argument.
If you think that there is a balance problem between SM ships and escorts then you should argue for fluffy fixes, not fanboy "I want everything" changes. As for my opinion, I think the reduction to 4+ for H&R attacks against escorts is a bad idea. Just make escorts cheaper, not assault boats useless.
The differences between a laser macrobattery (such as the common Sunsear Laser Battery on a Sword) and a lance are covered quite in depth in Rogue Trader sourcebooks. And since these cover the exact same ships we use in BFG, and, while rules for supporting fire from a starship are not yet in game, examples of it have been used already, such as in
Lure of the Expanse, where a dominator and a Firestorm both begin bombarding the planet the players are on. While the Dominator is flattening entire islands, the Firestorm is more selectively vaporizing structures. I would suggest that a Firestorm firing it's lance is most likely just what it says on the tin, since RT is also a Space Ships game rather then a ground based game.
And the fact that a lance hit can kill a wave of mantas is a fluke of BFG's rules attempting to balance AC with weapons, since the designers wanted Jutland, not Midway. It's sort of like Necrons phasing out when they've been curb stomping you the entire time only to have the last stand by a single squad of guardsmen kill that last necron needed to make their entire victorious army vanish and the IG win. In reality, the lance hit would probably kill one manta.
And, I'll point out something interesting for you: a lance fired from orbit in 40k has a chance for survival. A lance fired on the ground DOES NOT. This is due to the fact that dust particles in an atmosphere attenuate the power of lasers. The defense laser, which has stats for both 40k and BFG, (str 3, 60cm Lance) is a Str D weapon in 40k, and requires the power of an entire city to fire.
If you insist on fluff pointing out out anti-ship capability:
"Ranparre had several centuries of space battle experience behind him. Under his command, the ships of the Crimson Fists had saved over a dozen worlds without the need to drop any troops on the surface. Rebels, traitors, heretics, xenos, even warp-filth… Ranparre had beaten all kinds of enemy craft in high-orbital and deep-space combat. But he had never, in all his unnaturally long life, faced the kind of numbers that the Arch-Arsonist of Charadon was throwing at the planet now.
Even in the gaping black vastness of space, there seemed no quarter that was not under assault, filled with ork craft scything inwards on angry trails of glowing plasma.
“Order the Aurora and the Verde to close formation with us. I want the Aurora on our left flank, the Verde on our right. All forward batteries to target the command bridge of their flagship. If the beast Snagrod is aboard that vessel, we may still have a chance to end all this.â€
From a row of stations sunk into the metal floor on the bridge’s right, one of the weapons co-ordinators called out, “I have your forward firing solution, my lord. Permission to fire forward lances?â€
“Hold,†said Ranparre. “We fire together with the strike cruisers. If that monstrosity has shields, we must hope to overload them at the very least.â€
Seconds later, a comms-station operator on the left reported that the Aurora and the Verde had plotted their firing solutions, and were awaiting Ranparre’s order to engage.
“Give the signal,†barked Ranparre. “All forward batteries… open fire!â€
The central display screens in front of him crackled with blinding white energy as the massive weapons loosed their fury. Thick spears of light burned across ten thousand kilometres. A dozen small ork fighters and support craft caught between the two closing flagships were obliterated, simply wiped from existence. Then the lances stuck the ork flagship full in its gargantuan beast-like face." - Rynns World, Chapter 12.