The taxonomy of Invention components is unambiguous. It classifies materials into 5 groups (Common, Uncommon, Rare, Ancient and Other materials). The system as a whole works extraordinarily well with a few exceptions here and there (e.g. Crystal components might officially be Common, but they are much more difficult to come by than other common materials). One glaring issue that I think must be addressed, however, is the classification of 3rd Age components.
The ultimatum: Either create a new taxonomy class for "Super Rare"/"Epic"/"Legendary" components OR introduce additional sources for 3rd Age components into the game.
The latter solution does not have to reinvent the wheel! It can be as simple as reworking an item such as Third Age Iron so that when disassembled it yields components. Devs and others can quibble over the exact rates, but I think the current method of doing thousands of clues for a single component is, well, problematic.