I might well be remembering wrong so don't take my word as divine mandate. Maybe the devs can clarify this stuff someday in 2017.
Partially true. Twin-linked Avenger Shuriken Catapults are Exarch only while Fusion pistols are not available to anyone but an Autarch IIRC. Granted TT is not the entire cannon and there may be some of examples in the fiction based lore that may give precedence. Your point still stands however. The excuse of Exarch/Sergeant only does not hold any water based on what they have already done with other factions. Unless they want to clarify and specifically say that this logic will only be applied to the Eldar with around two specific exceptions.
Accessibility of upgrades is also part of balance. Eldar get the best premiums on armors on account of having no mid-tier upgrade, on the flip, the knife is a generalist tool on a race of specialists, of course getting a better knife would be more expensive than on a more rounded monkey.
Scorpion Claws are in the same place as Singing Spears, Witch Staffs, Mirror Swords, Dire Swords and Fire Pikes.
You can add the Reapers (Tempest Launcher) and Swooping Hawk (Sunrifle and Hawk's Talon) to your list of exception if i m not mistaken
I refer you to @Wulf 's excellent work on the subject http://forum.eternalcrusade.com/threads/a-treatise-on-loadout-point-costs-armor.60178/ On the subject that eldar armour is somehow better (excepting banshee, it's not). You're confusing costs and access on the knife, and ignoring the Electro Knuckles, which needs it's 150LP cost adjusted as well. Specialization doesn't mean they get cheaper or more expensive items, it's how they can access them (like meltabombs).
Well, if we're just talking about the claw, let's put it into perspective. It's a faster hitting powerfist, crushing through most other weapons, with an inbuilt shuriken catapult, that can be used from stealth. Makes sense that the Devs want to restrict it. We have a low amount of AV weapons, I know. We're short on weapons as a whole. But the Scorpions have never been for taking out vehicles, that's what the Dragons and Reaper Launchers do (and their means for doing so are being upgraded.). I probably wouldn't be far off if the devs were prioritising things like mandiblasters and chainsabres over other stuff to make the Scorpion more effective at what they do: Ambushing and eliminating enemies. Then again, if we want a melee base class to have better weapons, we should be thinking about the Banshees. If the Claw is Exarch-only, it'll mean it's not so bad that the Power Fist laughs at it. New weapons would be great, but our schtick is specialised classes, after all. They're gonna stick to their role, but Exarchs may get some leeway.
For the sake of balance, the claw could only be something similar to the power fist without the shuriken pistol attached to it. pehaps not canon but far easier to balance in the game. i am not even sure this game can handle dual wielding for 2 melee weapon.
Cost of an item is part of it's accessibility. It's okay for Eldar to get knife upgrades for their specialists, but it's also okay for those upgrades to come at a cost that's relatively greater than the more generalist factions pay for theirs. The game probably can, we do already dual-wield weapons, even in setups where only one of them is swapped(Warlocks/Sorcerers). The problem, as stated by the developers, is the animations needed to properly support it. Eldar already need another animation pass, adding dual-wield to the list would make that take even more time and resources.
