All mustang suspension is laughably outdated.
The suspension has been the same since the late 70's for the most part, so yeah, a bit dated.
You have to remember, Mustangs have traditional been cheap powerful cars so using older technology was okay, especially when it was very stout. Ford kind of forgot the cheap part though and cranked up the price.
The big three used to have the power to hand us a car and say "here you go, buy it" and we had to due to little choice. So we got handed shit. Even today they give us old Euro models and replace the good suspension and interiors with crap because they think they can still get away with it. It took them 20 years, but they are now finding the market does not work that way anymore.