Silver Spoon is one of the very little explored characters of the series who gave some indication that there was more to know about her than we were shown. For the most part her role was that of the sidekick of Diamont Tiara, but we got several glimpses of her being (for better or worse) more than just a follower. Concerning the worse Silver Spoon doesn't merely repeat or agree to what Diamont Tiara says but takes a very active role in the whole "blank flank" bashing of the cutie mark crusaders and Scootalo for her inabilit to fly in particular. For better, she is the first first student who applauds Granny Smith's story in the episode family appreciation day. In the background of Pinkie Pie's party planer song in "Pinkie Pride" we see Diamont Tiara trying to steal Silver Spoon's drink and we see Silver Spoon not having it (foreshadowing her standing up to Diamont Tiara in Crusaders of the Lost Mark). Given the confidence of Silver Spoon in Crusaders of the Lost Mark it would be interesting to know if she has any friends other than Diamond Tiara she would have been able to turn to after (for the time being) breaking up with Diamont Tiara.
As for her design I must admit I cannot help thinking of her as the most elderly looking filly in the whole show. The combination of her many silver / gray tones, along with the plait, the broad rimmed glasses and the pearl necklace all work together to make her look somewhat old.