there were people with useful skills (like Bannon) that helped get Trump elected. His skills probably don't help Trump govern. There are people with useful skills (like Ryan) for governing that didn't really help him get elected.
Does Trump see the Bannon wing as no longer useful and purge them? If so, we get standard GOP fare. America has always argued over stuff like tax rates and that can be changed at the stroke of a pen, it's not really structural to the American Experiment. that's just normal "to the victors go the spoils" stuff and if Americans don't like it we'll elect somebody else.
OTOH Does Trump see the Ryan wing as not useful to governing and keep the Bannon wing in government? If so i think we get alt right stuff and that is where we get into dangerous territory where we lose touch with our most important values. i think that also means we start getting wobbly on some critical international institutions like NATO, free trade, etc.
I can live with Ryan style GOP policy. that ebbs and flows. Bannon style alt right stuff is a non-starter for me.