There are quite a few, mostly USA Democratic party supporters, who are cheering Trumps rise not because they support but because they think him an easy enemy. They expect Hillary to crush Trump in a general election where her centrism will hold more appeal than "extremist" Trump. I think this is a miscalculation caused by interpreting a new situation through old patterns.
The idea is that Trumps large appeal among Republican base, as shown in the primaries so far, must mean he appears more conservative than other contenders. As this was the key to the success of various Tea Party candidates in the past, who used low level appeal to defy party apparatus. And Trump is following a similar approach of loudly opposing party establishment to gain primary votes.
However in policies Trump is a populist, not a conservative as such. He is not committed to the usual social wedge issues.
So I expect that if Trump faces Hillary in the primaries he will attack her from both the right - on law&order (email scandal), guns, and so on - and from the left - on trade, foreign policy, Wall street.
This way, not only would Trump take the popular positions in combinations others have not. But it will force the Clinton campaign to respond in ways that alienate parts of their own base. Those for whom "no more foreign wars" is a core issue will not appreciate Hillary calling herself tougher than Trump on the Middle East, for an example.