Basically, Seth only puts in the things that he likes. If you send something in, he (and all the other pre-viewers/listeners) will only put it on EqD if they like it, whereas what they should be doing (as one of the largest and most influential brony news sites on the web) is finding stuff themselves and reviewing it, as well as finding news out themselves.
Having to have someone send something to you is bad journalism. Sure, maybe if someone does send you something noteworthy that you haven't discovered and isn't incredibly famous is ok, but if you have to have an entire fandom submit things for your blog? It just doesn't work.
Going back to what I said before about only putting things that they like, brony rapper Yelling At Cats revealed in a thread on /mlp/ that he was once a pre-listener, and that Seth told them that they could only put on things he liked, instead of reviewing and critiquing, like a proper news/media blog should.
Also, all of the popular musicians/authors/artists will get featured no matter what. A great example is The Living Tombstone, he will always get his things on EqD no matter what. It is a rarity to see unpopular artists get featured on EqD anymore. I recall seeing a non-pony song (a cover of 'Up All Night' by Blink-182, covered by ShadyVox) being put up.
I personally think we need a new brony news blog. I for one would actually be willing to start one, but I don't think I have the time to do it.