I think I've said this in another thread, but it's okay for one work to have references to other works so long as it isn't overbearing. Megas XLR had a lot of references, but for the most part they're kept in low quantity and pertain to the setting and backdrop. Almost all of them were about mecha, kaiju, and other /m/-related media.
With Steven Universe I'm noticing innumerable direct references to a wide variety of series, including but not limited to Yoshi, Usagi Yojimbo, Sonic, Tiger-Man, Eva, Mazinger, JoJo, FLCL, Cowboy Bebop, Junji Ito horror stories, Akira, Dragon Ball/Z, the list goes on. Some episodes are using reference after reference after reference, and for many of these references it's simply copying them scene for scene. It's starting to get a little too much and, although I will say that the show at least makes sure they don't look out of place within the flow of the episode, I would like it if they did start toning them back down to Season 1/Early Season 2 levels.