The biggest problem is that it concentrates an unbelievable amount of power into the executive branch, and specifically the President, himself, if this slides, or can be reasoned away as just another “political gift”.
Step back from the details and look at the big picture. The President, abusing the inherent power of his office, sought to influence absolutely the outcome of an election by offering an executive post to one of the candidates. And when I say absolutely, I mean, the candidacy becomes null and void in exchange for something of value (it has to be considered more valuable or else it wouldn’t be offered). If this is validated as “business as usual”, then there’s no stopping the president from influencing elections, votes, state policies (hello, Arizona), etc., by simply throwing someone a bone in exchange for something that accomplishes the will of the President, instead of the will of the electorate, who are endowed with that authority. i.e., your President is now a dictator, having disenfranchised all voters with his singular position of power.
THAT’S why this is a big deal.
Make no mistake. This is big and must be investigated. In fact, they should investigate obama's senate seat scandal while they're at it. I don't care what color he is, this cannot stand and the press needs to do its job.