Since the MLP production staff at San Diego Comic Con confirmed Fluttershy's brother would appear in the second half of season 5 (later this year!), I wonder how "Shy" will react to her male sibling.
If "Shy" is younger than her brother, will her brother apologize to her for failing to be an adequate mentor to her? If Fluttershy is older than her brother, will her brother visit Ponyville and complain that she has failed in her role as Big Sister? Maybe something similar in the episode Amending Fences where Twilight returns to Canterlot and has to deal with Moon Dancer?