Not sure of what all the particulars were but that seems to be the difference from past is that those that were choosing to come here actually wanted to contribute to society and not be sponges.
One of the changes is that in the past, they didn't have entitlements thrown at them. I'm much less concerned with illegals that come here to work, whether over or under the table than I am with those that come here specifically to get on the multi-generational entitlement gravy train. Banning entitlements to non-citizens (outside of emergency services) would be a good start to immigration reform. Doing what many countries that are considered more progressive and enlightened than the US, like Australia and New Zealand do, and requiring people to have a job or else show they have enough money to support themselves, would be another good reform as long as the path to citizenship is streamlined.
I have a friend from Canada that has been struggling to stay in the country even though she has the proper visas AND has a job. She was working as a contractor doing scientific work for the .gov in my office before I left, and as soon as her contract was up, immigration was already on her telling her she had to go back to Canada unless she got another job in 30 days (she did, a crummy one, but it was enough to keep her here while she looks for something in her area of expertise). Somehow they have the resources to keep tabs on an individual (she had to report in person to immigration at the Tijuana border on a regular basis) that came here specifically to be productive, but ignore people coming here to be leeches.
You'll find that some of the people who hate the southern border situation the most are the people who stood in line (sometimes for years, like my parents) to come here the legal way. Kinda like when someone cuts to the front of the line at Walmart and pays with EBT while you're standing at the back of the line with cash.
