I think of Denarians sort of like this:
Each Fallen has a suite of powers. There's probably a lot of overlap in what this would look like in game terms, even if the flavour would be different. Each also has a personality that guides how they go about adding these powers onto their host and at what pace. So, some push for control, while others offer partnership, and this corrupts their hosts at different speeds and in different ways.
Then, each host has predispositions. Some are blanks slates in terms of supernatural power. Others are power houses to begin with. They all vary in inclination and in the degree to which they could resist the will of a being like the Fallen.
Now combine these two. Some variations will have chemistry, while others will not. Willful hosts combined with controlling Fallen will end up with something akin to driving a car with the parking brake on. The better the chemistry between Fallen and host, the more powerful the combined being ends up.
This means it'd probably be difficult to come up with a truly representative generic Denarian template, because they really are a collection of individuals.