While it may "seem" improbable that the "horse and cart" style suspension can work commensurate with more modern designs, I can assure you that there are many cars here in the US (of all brands) using this system and putting a spanking on the newer cars on the race tracks and streets around the US. As stated there are a number of trade offs with every system, manufacturers attempt to cater to the masses and use systems that give them the best of all scenarios while remaining committed to the overall design and cost effectiveness. In other words, manufacturers do not use what is best for any specific application typically (for mass produced cars sold to the greater community, not referring to super and hyper cars). That said, the Mercedes inspired suspension of your Challenger is very effective and does very well (I own one as well); however that doesn't mean that other systems don't work or even work as well. Cars and especially custom, old and/or modified cars are all about subjectiveness, perception and preference; what one person likes/wants is not universally accepted; some will agree others will not. Bottom line is that a car is what you make it or want it to be. Building a restomod E body is awesome if that is what you like; if it is just something that looks cool then you will forever be picking it apart and not being as good as something else. Most of us on this forum grew up with these cars and as such have a love for them. I can say without hesitation that my 2010 Challenger is much more refined than ether of my "old" E bodies and I love it, however I love my 70 Challenger and 73 Cuda for what they are; not what they aren't, I accept them for what they were designed as and what they are now. Can an 70's era be made to handle, stop, etc as well as a modern LX? Sure, it is well represented on this forum. That said, are they the same at the end of the day? No, they are different vehicles. This doesn't mean one is better than the other, it is all about perception, acceptance, desire, enjoyment, etc and what is important to you.
Sorry for the rant, its one of those days.