People can be as creative as they'd like to be, although yes, I recognize special/rare OC's can get a bit distracting/annoying. Some can be unoriginal and even make up their history to be somehow related to the main cast of characters in the show. Some also use very bright colors and unrealistic features & talents.
The quantity of unrealistic/unfitting characters has been growing through the time at the actuality. And mostly they are poor while coming up with interesting roleplay scenes. They powerplay, and that's not good.
Still, there are realist people who prefer to keep their characters unique but simple. An earth pony with warm, pastel colors and an interesting story & a chronicle of their cutiemark can make up an interesting character.
The number of realist people are decreasing, but still standing strong. One day, the unrealistic character count will decrease and everyone will know what real creativity is. Although I believe that will not happen sometime soon.
Apart from that, you can make a powerful character, even an alicorn, but if this character has personality or physical difficulties.
An example: A warm golden alicorn, with a short, flat mane with tints of orange, brown and white. This alicorn is in her late teens, having a difficult life going through royal education & manners. Prefers to dedicate to general farming. This alicorn also seems to have a damaged horn, which doesn't let her use any powerful magic spells.
Thing is, the count of difficulties should be the same to the count of talents, or at least half of the count of the talents. Keeping a character realistic is making them different. Not all ponies are perfect. Even Celestia might have a hidden difficulty.