hi clo,
i think most new presidents are in part a reaction to the failings of the old one.
obama seemed smart after the apparent intellectual limitations of dubya bush. dubya seemed to have rustic integrity after the cosmopolitan slipperiness of clinton. clinton seemed vigorous and creative after the golf-club dullness of pappy bush.
i don't think trump is distinguished from the other contenders by his desire to end obamacare. it is his stance on immigration which stands out. it was when he started talking about it that his poll numbers went up.
for myself, i think trump's solutions are nonsense. but his popularity tells you what the problems are or are perceived to be.