I honestly do not think that Twilight is overrated or she is getting all of the attention. To prove this I will be going over each episode of season 4 individually and briefly going over seasons one to three. *I realize this is a bit of a touchy subject so while I don't mind comments I expect that those who comment will do so respectfully.*
Princess Twilight Sparkle (Part 1 and 2) - In this episode, Twilight does play a major part, but so does the rest of the mane six and Spike and Discord. So while the title may have her name it is not solely about her. Also, it can be inferred from this episode...
Trixie's Cutie Mark: This may sound weird, but I think her cutie mark is fascinating and simple at the same time. I love the colors, a light mix of blue.
Sunset Shimmer's Cutie Mark: Her cutie mark represents her very good. The colors go well together, because they are the same colors as her mane, too. The suns' rays are wavy, just like Celestia's.
Zecora's Cutie Mark: Zecora's cutie mark is well detailed. The swirl represents the her personality well, and it looks as if a mark that a Zebra would have. It looks like it represents her oddness and her reasonableness.