Ya, I was wondering where you got the "Ashara Dayne is a wildling" part.
I can see where Stark blood overpowering Targaryen blood comes in to retain Jon Snow's warg abilities though.
The more I think about it now, it could well be the reason George Martin had Jon Snow decline Stannis' offer to be declared a legal Stark and be Keeper of Winterfell was to have a potentially dying Stannis (who is currently King after having beater the Lannisters and Boltons but defeated by Aegon) declaring Jon Snow a true Targaryen. Jon Snow and Daenerys could then team up against Aegon and win. Lots of if's and but's here but I guess I changed my mind.