That's part of my problem with exotic/unique packs going into advanced assemblies (I could care less if they're used in Ultimate Assemblies). Because you're slapping an overpowering modifier on a weapon, you know that you're going to get an overpowered weapon out of it, whether or not it's an assembly. Yeah, I get the idea of rewarding actually using the mods with a new toy and a mark in the Player Stats, but it's just silly to have so many middle-of-the-road assemblies that require awesome tools to make - especially when a Nano Mod Pack serves me better on my armor than it does going into an advanced assembly. If I were making an Ultimate Assembly, then yeah I'd use that, but still.
According to the Wiki...
Of the 19 Basic Assemblies, 4 require special mod packs - Power Armor and Plasmatic Shrapnel require Nano Packs, while Plate Armor and Lava Boots require Onyx Pack. 15/19 (a nice 79%) of the Basic Assemblies can be built with just the standard four packs, while the remaining 4 are evenly divided between Onyx and Nano.
Of the 14 Advanced Assemblies, 8 require special mod packs - Energy Pistol requires Sniper; VBFG9K, Nanofiber Skin, Gravity Boots and Nano Shrapnel all require Nano packs; Storm Bolter Pistol and Assault Cannon require Firestorm; Fireshield requires Onyx. 6/14 (a measley 43%) of Advanced Assemblies can be built with just the standard four packs, while half of the others require the Nano pack. Bear in mind that the Nano Pack and Onyx Pack are Unique items. Unique items with no guarantee of appearing.
Like I said before, I could care less about how bad the Master Assemblies are on requirements, but here are their numbers anyway. Of the 7 Ultimate Assemblies, only two of them - Cerberus Armor and Cerberus Boots - can be made with just the standard four packs. The remaining 5 all require a Nano Pack; in addition, the Cybernano Armor also requires the Onyx Pack, while the Biggest Fucking Gun only requires the Sniper Pack
Out of all the assemblies, the Nano Pack is used in 11 of them (Out of 40 total assemblies - that's 27.5% of all assemblies)
At first glance, it seems weird that you can't use Exotic Packs in Basic Assemblies, but any monkey could slap a power and onyx mod on a red armor, while it takes some real knowhow to turn a Tactical, a Bulk, a Firestorm, and a Pistol into the Storm Bolter Pistol.
Dammit, I can't count past 11pm...