This is a circular argument. The only reason you don't think he's a legit candidate is because you're short-sighted enough to think you can only vote for one of two choices. You're perpetuating the two party system by saying a vote for Johnson is a vote for Hillary. Some polls have him in the double digits, and some have him drawing more from Hillary than from Trump. Uneducated voters are the problem. They either don't know there are other options, or they think that the other options aren't realistic. I got news for you, if they're on the ballot, then they're realistic options... if the educated voters will actually do something other than live in fear that not voting for one of two awful choices were a wasted vote. The two parties WANT you to beleve you're wasting votes by voting for someone else. Right now, they don't have to field the best candidate, they only have to field a candidate better than one other party.
It's like the old saying, when two people are being chased by a lion, you don't have to be faster than the lion, you only have to be faster than the other guy. Well, when it comes to this country, I don't want just the better of two shit options. More options breeds better options. But until people get over the two parties, the system will continue just as it has, whether it's Trump or Hillary.
And Trump's not going to expose corruption. It's just more pandering. He's been corrupt in his business dealings, why would you think he's going to expose corruption when his administration is running things.