While I've dabbled with Realms of Power: The Infernal before, I've never built a full-on infernal sorcerer before, so I'm surprised now by how expensive it seems from a Virtue perspective, at least compared to other subsystems I'd compare it to. With the exception of Elementalist (which ngl wouldn't be very good even if its costs were brought in line with other traditions), most traditions that don't require the Gift and follow the TeFo formula have the Techniques as Major Virtues and the Forms as Minor Virtues.
This is true of Gruagachan and Learned Magicians on the Hedge Magic side, as well as Faerie Wizardry (I don't have a copy of RoP:D on hand, so I can't check as far as the Divine Realm). And given the number of each, this means that a Mythic Companion can, at the player's option, spend about half of their Virtue allotment (a little less for Gruagachan, a little more for everyone else) to have the whole suite of options at their disposal, leaving a fair bit of room leftover for whatever else they want their character to have going on. Heck, this is also the rough scaling followed by the Ars alternatives - the Ars Goetia and Ars Fabulosa both have four Major Virtues comprising their skillset, so again, about half of a Mythic Companion's loadout.
This makes sense to me, as a Mythic Companion is meant to replace a magus, and while none of these traditions can match the power and versatility of the Hermetic Arts (nor should they), the "amount of fun supernatural things you can dabble in" quotient should be similar. It's also affordable enough that regular Companions can, for roughly half of their 10 Virtue slots, still carve out a niche within the tradition - something like four slots for a single defining TeFo, or six to access a breadth of capabilities within one Technique.
But... Malefica don't get that. Malefica have two Methods and six Powers, which is pretty in line with the other groups discussed here, but ALL of the Maleficia are Major Virtues. This means an ordinary Companion gets a single TeFo for over half their Virtue allotment, and a Mythic Companion only gets 3-4. Now, granted, I vaguely recall this being how the Divine side works, and I recognize that the rationale for spreading out those abilities so much is so that individual sects/traditions are differentiated from each other. But in practice, given that neither side of the Malefica TeFo is Accelerated and that each combination has about as much breadth as a TeFo for any other group (albeit more for the individual, since you don't have to design formulaic spells or anything like that), it sort of makes diabolism feel weak and expensive, rather than enticing and oh-so-easy to give into.
I'd also argue that this probably wouldn't be unbalanced given all the huge asterisks that come with wielding infernal power in the first place. Sure, being a sinner surrounded by other sinners can be fun - orgy, anyone? - but the average number of stable relationships a diabolist is likely to have rounds to zero, given that the Divine Realm and its stranglehold on every level of society will get you murdered by your loved ones and everyone else if discovered, the largest and most powerful representative order of the Magic Realm has a similar policy (and since you're not actually a demon they can sniff out your powers just fine), your fellow diabolists are liable to backstab you to get ahead, and your demon benefactors will probably abandon you if a hair-brained scheme goes belly-up or dispose of you themselves if you step out of line. That's a whole lot of baggage, even weighed against the Gift, so I think it's fair to suggest that they ought to get more out of it than they currently can.
So I'd probably take the standardizing approach, keeping the Methods as Major Virtues but changing the Powers to Minor ones.
What do you guys think?