"has really galvanised the right wing and center of American politics"
Not exactly. Cruz and (to a slightly lesser extent) Rubio are the right and Kasich is clearly the center.
Trump's promises are inconsistent with any established GOP faction. And he frequently contradicts himself from one day to the next. ("Let the Russians take care of ISIS" vs. "Let ISIS depose Assad, then we'll do the rest"; "Register Muslims!" vs. "We're not going to do that.")
Trump's followers are populist know-nothings under the spell of a "leader"w who can do no wrong because he's a TV star, a billionaire, a supposed tough guy, an aggressive nationalist, a low comedian, and a vulgarian who claims to have a simple solution - himself - for every problem.
There's no telling *what* President Trump would do in office, but any "change" would undoubtedly be in the direction of inconsistency, nationalism, craziness, etc.
Congress would be hard pressed to keep him in line.
BTW, besides boasting about the size of his whanger at last night's debate, Trump said that Sen. McCain, who's warned against a Trump candidacy, "has to be very careful."
And why? "He'll find out."