Marius and Heirs of Alexander DLC are clearly NOT major Expansions. Reworking existing systems is not adding additional mechanics like in similiar expansions for other paradox titles
But this is not the fault of the current developer teams, they had to overhaul the existing systems
I guess that means Holy Fury, which reworked Crusades, Catholicism and Holy Wars - which have all been in the game since release - was not a major CK2 expansion either then.
EDIT:
To elaborate, since I try to not
only be sarcastic in these replies, expansions can also
expand on existing mechanics. It doesn't have to add completely new ones. In fact, the expansions that expand and elaborate on the existing mechanics are often more valuable in my mind to the game in the long run, as making the foundations of the game more intervowen and realized makes for a rock solid core experience that can be further developed with flavour for regions and nations and the like.
What IR is doing in spending its early expansions reworking and expanding on existing mechanics for a more focused vision is a good thing, and its major patches - the expansions - have all been some of the most consistently monumental and well-rounded ones we have seen in a Paradox game.
