BEFORE I run this past my SG, to be rejected/modified/accepted, I wanted to run this virtue idea past y'all.
I like the Skilled Parens minor virtue, and was pondering a major virtue version. Kinda like 'Strong Faerie Blood' as opposed to 'Fearie Blood'...
What are y'alls thoughts????
Exceptional Parens
+90xp +45spell levels
Hermetic Prestige
Minor Magical Focus
Minor Flaw 'Proud'
Sounds like a fine idea, however I would probably switch the mmf for something like Puissant Magic Theory to account for the exceptional tuition. MMF makes it slightly overpowered IMO. Alternatively you could offer a number of options from which two additional benefits and one flaw could be chosen.
For example:
Study Bonus, Apt Pupil, Puissant Magic Theory (mentioned above), puissant Parma Magica (was taught more about Parma earlier in the apprenticeship perhaps), Puissant Finesse, Puissant Concentration, etc. This could all be represented by saying the filius gets the added xp and spell levels plus two minor virtues and one major flaw or somesuch.
Just a thought.
The idea is fine as a concept, but you're not really getting your money's worth (2.5 virtues and a flaw), especially as it would be a Hermetic Major virtue.
Consider taking them as separate virtues and throw in something like "Gild Training" from Guardians of the Forests for XPs on the side to let you take you more arts (I can't remember if it also gives you some spell levels)
How about this for the package...
+3 Exceptional Parens; includes...
Skilled Parens
Hermetic Prestige
Arcane Lore
Educated
Mentor
eh?
Our SG allowed us to take skilled parens twice, indicating a "Very Skilled Parens" but in that case did not permit other odd "training" virtues.
-Ben.
Really not a fan of Virtues/Flaws packages, as they allow you to circumvent the usual 10 max V/F limits.
=> I would advice taking whatever virtues/flaws you want within the limit, saying they come from your exceptionnal parens, but not creating such a "pack".
spoilsport 
lol
I would argue however that, especially at play start with chargen restrictions, a major virtue ( or more aptly the major virtue slot it represents ) can or should be worth more than the numberical sum of three minors. So the idea of a 'package' of minors being added together or modified to make a 'major' version of something makes sense to me under some conditions.