WotC felt that it was necessary to prove to us that they could, in fact, still print bad Goblins. After Sparksmith, Piledriver, and Warchief, some of us were beginning to wonder.
I'm starting to get the impression that WotC's little R&D team is comprised of a few different groups...
Those who think they can make an old thing better, think they can make something new that is really good, and those who just like to carbon copy older cards.
Mons's Goblin Raiders isn't even good as filler. I counted around twenty other Goblins with casting costs of one red mana, all of which had some ability. Not all of them were very good abilities, but none of them were always harmful and all of them could be harnessed to make them useful.