The only real argument they have for Trump with Cruz at a disadvantage can be expressed in the oft repeated verse, "Joseph cried". Almost every second line Joseph is mentioned in Torah, it's to say he cried. Why was Joseph crying alot? He wasn't afraid to show his emotions. He kept doing it as the president of Egypt.
Trump expresses his opinions in a reactionary style, and even though to a seasoned marketer like me, I recognize every little tactic, and how every absurd message is really to endear him to segments of the population and make him look good where he or others are weak, he makes it look emotional and authentic.
Cruz has stuck to a strict campaign plan, and as impressive as it is, he's also strictly regulating his emotions, and is being the stereotype as much as possible of a strong leader. It's hurting him.
Cruz did a pretty silly ad where he tried out for Simpsons characters, and I couldn't help but wishing that he showed that happy and sort of quirky aspect of his personality more. People would relate to it like they do the characters on that big bang show.
To finish, everyone can tell if you're not emotional about this race, you're a phony. The stakes are the country's economy, and nuclear genocide. People want to know that their politicians are with them on the issues, and it hurts me every time I see Cruz swallowing down his feeling before he replies to a comment from a focus group, because they would love him all the more if he just laid it all out bare, stayed respectable, but wasn't afraid to let his emotions fall out of his eyes and mouth.
The closest thing I've seen him come to it besides that ad is taking on Trump. You really felt a connection to Cruz by how strong his emotions were in regards to the disaster that has been and may continue to be Donal Trump.
So as strange as it'll sound to someone who doesn't already know, for the same reason that Joseph was so beloved in Egypt, Cruz needs to break down his learned inhibitions, and cry.