AluminiumWolf said:
Fundamentally, never getting in a fair fight is just common sense and/or a matter of circumstances. That won't change no matter what you're doing or with what characters. Fighting smart, using your advantages and your enemy's disadvantages to the fullest is something that should never be disregarded, whatever the nature of the player characters.
The differences aren't there.
An Acolyte has, as I have commonly told my players, exactly enough freedom and authority to get themselves in trouble, but never quite enough to get themselves out again without a good mixture of skill, luck and cunning. Once they're on the ground, a cell of Acolytes has the freedom to operate as they wish towards the end of uncovering threats to the Imperium - groups of adversaries that are inherently (and justifiably) paranoid about being found out by the authorities. The scope is an investigation, with healthy doses of politics and violence thrown in for flavour. What an Acolyte does is a task ill-suited to armies of Guardsmen or squads of Space Marines.
Where it differs between Guardsmen and Astartes is both scale and scope. A squad of Space Marines can achieve things that a company of Guardsmen cannot, and vice-versa (everything has its place, and Space Marines simply don't have the numbers or tools for a variety of tasks). A person playing a Space Marine has access to a different range of tools (in the forms of character abilities, wargear, and viable strategies and tactics) to a person playing a Guardsman, and thus can approach a situation differently.
Consider the following combat situation from the perspective of two forces. The first is a platoon (4 squads plus a command section) of Imperial Guard Infantry of a decent standard - Cadian Shock Troops or similar - armed with a good variety of heavy and special weaponry. The second is a five-man Deathwatch Kill-Team consisting of two Tactical Marines, an Assault Marine, an Apothecary and a Devastator. The situation is as follows:
A densely-built urban area, roughly 400 metres square, used as an encampment by Orks. Several ruined buildings form the outskirts of the area, reinforced with crudely-built but solid-looking barricades made from rubble and scrap metal. Sentry towers dot the edges, mounted with crude guns and manned by Gretchin slaves. The inner section consists of three buildings that are more-or-less intact, with holes from artillery and bombing runs patched with sheet metal bolted into prefabricated slabs of ferrocrete. Two of the buildings are former hab-blocks, each five storeys high with numerous windows covered by plasteel riot shutters - fairly defensible, but not fortified. The third is a thirteen-storey Administratum building, separated from the hab-blocks by a broad street. The Administratum building is designed to be able to withstand civil disorder and impress upon those nearby the might of the Imperium, and as such is solidly-built and fortified by design. Thermomantic augury performed by Priests of the Machine suggests that there may be between thirty and fifty Orks and between fifty and eighty lesser greenskin organisms present within the area, while recent recon suggests that they are well-armed with heavy weapons and are constructing an artillery battery on the roof of the Administratum building. It needs to be cleansed of their taint.
One situation, but the Guard and the Deathwatch will (and should) approach the situation differently - Space Marines can succeed at tactics that would be suicidal for the Guardsmen, while the Guardsmen have the numbers and the firepower to approach the situation more methodically and thoroughly. The experience of playing a Deathwatch Space Marine comes with having all the tools, advantages and capabilities that define a Deathwatch Space Marine, and employing them to their fullest.
It's one thing to have a challenge, but it's another to ignore statistical probability in a game that involves rolling dice. Now what Nathan has said elsehwere is correct that balance can be inherently subjective and there's also the fact that writing a balanced game is exceptionally hard if not impossible, especially where the game has so much freedom of choice like an RPG. But, as I just said, ignoring statistical probabilities in a game that involves dice is a bad idea. Say for sake of argument the Hierophant did 10d10+50 damage with each attack. You could easily justify that from a fluff perspective, but think about from a dice perspective - that's an average of 105 damage. Even when you factor in the frankly pathetic Pen that all Tyranids have, that's still more damage than any Marine can take. It doesn't matter if the game is about heroic sacrifice or the cost of a real challenge and a sense of accomplishment when you can be squished in a single hit like that. Fate Points only get you so far, and games where the difference between participating and not participating are a single dice roll (rather than a struggle) can be quite bad for making the game fun for the players, no matter how realistic it was.
