There is nothing to fix in terms of the immigration system. It is just hard to get a green card or a visa that allows one to stay and work here. The laws are clear and do the job. The problem is with those who try and go around the laws, and that's with everything, like evading taxes or building without permission.
The rest is baloney as it comes to illegals. There are all sorts of illegals, including those who overstay their visas, and they usually are northern european these days. The ones Trump has a problem with are those who speak spanish, and come south of the border at night. The rest don't concern him because they are blonde. Unfortunately, that poor woman he put on stage about having someone in her family killed said that it was a "russian who overstayed his visa", and then said "vote Trump". Problem with it is the guy came here legally, and committed a crime. We already have laws to take care of that. The public is mostly stupid and can't tell shit from shinola.