Eh. The two parties used to be a lot more similar, never with Clinton or Obama was the dem-or-else mentality particularly strong. Swing voters have gotten rarer, but they used to be quite common. That's a person that will vote for either party, depending on the individual. This was sensible because they weren't as far apart from each other.
I mean, particularly with Obama vs Romney. Obama's signature achievement? Obamacare. Romney's signature achievement from his time as governor? Romneycare. And they were extremely similar, policy-wise. These folks tended to get called "moderates", and it didn't really much matter which party they were a "moderate" of.
Now the choice is between one of those old moderates, same as we've had, and a wannabe dictator. So, Trump makes things special.