I get it. I felt the same way when the S550 was first released. Personally, I prefer the exterior design of the late S197s and even the S650 over the S550, although I do think the S550 has the best interior.
The SRA on the S197 is still impressive and holds its own in terms of handling, so I don’t feel like I’m missing out much.
Right now, I’m trying to persuade my brother-in-law to go for a 2011-2014 Coyote. I think I’m making progress. 
2011 GT in Kona Blue with just 37,xxx miles on it.
I really love the amber and orange fog lights on your '11 and '13 models. The '11-'14 S197s are my all-time favorite Mustangs, but I might be a bit biased since I own a 2014 GT with a glass roof. It’s approaching 115k miles now, and I’m hoping to enjoy many more miles with it.
That’s great. They can last you a lifetime if you take care of them. Plus, when they break, you can make them even stronger. 
There’s something about the hood not being integrated into the front bumper that gives it a cleaner look. I can’t quite put it into words, but it evokes the classic designs of the '60s and '70s.
I drove my 2011 for 14 years and covered 120,000 miles. I only decided to wholesale it because I live in the rust belt, and the underside was starting to show signs of rust. I bought a 2022, which is a fantastic car, but I can’t help but miss my 2011. That car was pure elegance, with power to spare and killer looks.
My favorite modern design of the Mustang is from the 2011-2012 model years.
I agree; it has a modern feel while also being retro.
21 is by far the ugliest.