Asking the president of a nation to dig up "dirt" on a potential political rival is a "thing of value" for an election.
Right, so Obama asking foreign spies to invent information is a crime. He did it in secret because he knew it was a crime, he illegally spied on the opposing party's political campaign to favour his own party's candidate, crimes way beyond what Nixon did with Watergate. It wasn't just a few hired hands, he was using the CIA, FBI and DOJ to do his dirty work.
As for Trump, he hasn't asked anyone to "dig up dirt" - he's asking them to investigate what appears to be clear corruption by a senior government employee. He's doing it out in the open. There's no crime here.
But if you think there is, then impeachment proceedings against Obama can begin ... right? :)