Im new but I can't see how it's too lopsided of a trade at all.
Ratings-wise Riggs looks to be awesome, but as moy23 pointed out, he has been pitiful so far in the big leagues. So he gets rid of a guy who has been a BIG disappointment for a Long R who has been pitching 150+ innings and doing it pretty well the past few seasons. He also gets a pretty solid defensive guy, who could definitely play 2B, and maybe he develops into an actual BL SS. He can't hit very well, but when he does, he will hit for some decent power, and he should steal some bases.
The other guy gets a "potential" lights out closer (maybe the change in scenery will do him good), for a Long R who is nearing the end of his career, and a 2B/SS that he may never have planned on using anyway.
I can definitely see both sides and therefore I'd say it isn't rape by a longshot.