A "points-based" system is meaningless. You could have a points-based system that says "100 points if you have a pulse" (which is not far off our current one...)
The two significant changes our legal immigration system need are (1) a hard cap on visas issued, similar to the US - once the cap is reached, that's it sorry, you have to wait for the next month/quarter's availability.
And (2) differentiation of rules for different countries. Currently we try to manage issues with restrictive rules that apply to everyone, for example, requiring high salaries to sponsor spouses. These rules then catch completely non-problematic immigration like a British guy falling in love with an Australian bartender or something, but don't do anything to restrict, for example, clan-based chain immigration where everyone in the family will work together to create some fake job with a salary that they pay back secretly in the home country.
People who are more culturally similar to us (Australians, Kiwis etc) ironically will NOT try to cheat the system like that so they are the ones who ended up being excluded by it.
FYI: many Australians for example are completely genetically British and have lived their whole lives in a very similar culture, but are not eligible for ancestry visas because the ancestry is from the 1800s. Meanwhile you get stupid examples of terrorists in the middle east being eligible for "ancestry" visas. I think this is something that surprises a lot of people who aren't familiar with the system.