That's a very good point, especially as a scout captain tends to be a fully fledged marine, if not a champion.
Not to mention the Space Wolves very own Wolf Scouts are entirely made out of veterans instead of neophytes. Hopefully this is represented in game for the Space Wolf scout class if they make a scout class. I can imagine there are practical reasons for swapping out power armor for some missions that require stealth, or even less bulk/more agility to navigate certain terrain. Heck being able to raise your arms above your head a bit more is one major benefits of scout armor over Power Armor that have to restrict movement of at least the arms due to those big pauldrons. The ability to climb or guard against overhead melee attacks lol.
Power armour does not restrict movement. It is stated repeatedly in the lore that it doesn't and I can't think of a moment when it would prevent movement or climbing.
Wolf scouts are veteran grey hunters and may choose to wear scout armour or power armour, if they choose power armour they lose their stealth/infiltration bonuses.
There is no way that a Space Marine with those gigantic pauldrons could put their arms out to their sides and raise them above their heads (Lateral arm movement). It is physically impossible for the ceramite pauldrons to not clip into the clavicle or neck area if they try. If the arms go straight up the pauldron itself may even be inside the marines head. By standard Space Marine pictures these guys wouldn't even be able to lift their hands up and touch their own shoulders either, and would have a very hard time reaching their backs with the pauldrons and raise power unit in the way. Needless to say just from losing their lateral movement just below shoulder height on its own would make climbing fairly difficult, not counting the hand to shoulders being an issue as well. As for other movements that are not hindered by the physical shapes of the armor, yes the armor actually enhances their speed and strength but that is not the issue in this case. Weight and sound still are a factor when moving "stealthily" weight on certain surfaces, and the armor has to make some noise that is more audible than organic bodies. These guys must weigh like 700lbs in armor (Not counting weapons, equipment, and ammo) and would even have a hard time in regular human urban terrain like clearing houses, they would be falling through shoddy floors and stairs...thinking about it makes me sorta laugh at the image of a Space Marine kicking in a door to find cultists in a house only to plunge through the crappy wooden floors lol. Ultimate fail would be a single Space Marine getting in a human sized residential elevator which holds maybe 800lbs lol
The only problems I see with a chameleon type camouflage or hiding in the shadows would be that many players set their brightness up to ludicrous levels just to spot them instantly. Others may have a lower-quality PC and need to turn off shadows.
Are we forgetting the Raven Guard? The masters of stealth warfare and they still wear power armour. Admittedly they modify it a little bit but it's effectiveness isn't reduced nonetheless In terms of climbing I urge you to watch the Ultramarines movie. Bad as it was it did have a scene that involved one of them almost falling of a ledge and one climbing up a near sheer cliff-face. I would link it to you on youtube but google has ruined it (youtube). However I do agree with you that scout armour should be used in preference to power armour for scout classes. I'm just trying to prove that it is not impossible to have stealthy power armour nor does it restrict movement in a combat situation to the point where marines would be incapable of performing.
