They were legitimate concerns. Right now, and for most of us, we have little objections to his serving as Attorney General (so long as he goes hard into making sure the immigration laws and deportations go into full effect — which was another issue he was squishy on in 2008).
In regards to this thread, I’d say several of the candidates would have beaten her.
As Cruz is of Cuban descent (and this is true of Rubio as well), he would have done better among FL Cuban-Americans and probably scored a little higher among FL Hispanics in general. Florida would have been mostly locked up from the outset. Would have won North Carolina. Ohio would have gone Cruz as well, but more narrowly - he would have traded a lot of Trump’s NW Ohio votes for bigger margins in the suburbs. Would likely have won Wisconsin - he’d have run further ahead in the “WOW” counties but behind Trump’s numbers in the LaCrosse area. He probably would have run better in the West, picking up Colorado and Nevada, possibly New Mexico, but not run as well in a lot of the North - I doubt he’d have won Michigan or come as close in Minnesota, Maine or New Hampshire as Trump had.
Scott Walker would have likely carried Wisconsin and Iowa, possibly Michigan, if not, I’d say probably Colorado and maybe Virginia. Minnesota was a possibility but probably still a narrow miss.
I think a mix of the above two scenarios would have fit most of the candidates like Paul, Fiorina or Rubio.
I think Jeb would be among the most likely to lose. It’d have been tough for him to argue himself as a change candidate as yet another Bush. And as the primary proved, he was a weak and lousy candidate. Hillary would have had a field day arguing that another Clinton admin would be better than another Bush. Jeb would just have never had the passion behind his candidacy that Trump had. If he won, he would have limped to victory with a narrow margin.