Hi John,
You mention the loss of the ability to hear high frequecies that is normal with age, I am 54. What do you, Brian and others believe is the value of extended response to an older listener. I find myself more sensitive to the lower treble not less so as I age. I am curious as to the interaction of the upper treble on the rest of the audio spectrum and in particular for me the sensitiive lower treble.
Hi Turk,
While hearing ability is almost as "individual" as a fingerprint, it is even further affected by the fact that it "adjusts" as we age. The problem is that this adjustment is not the same in everyone.
Just like eyesight, some begin losing significant High Freq abilities, early and some later. Additionally environmental factors can enter into the loss like exposure to high SPLs and such.
But, this "loss" is not total in most cases, but "rolled off", which means that you still hear those frequencies, it just takes higher SPLs to take them into our awarness.
Your sensitivity to a specific frequency group might mean your tympanic membrane is (or has been) damaged and scarred. Many times this comes from ruptured eardrums that occured when you were a child (probably an ear infection when you were cutting teeth).
Later in life as your HF hearing begins to "drop/roll off" it reaches the resonant frequency of the scar tissue and "Bob's your Uncle",

a sensitivty arrises.
Now this is just one scenario of many. Generally with healthy Ear Drums "extended frequency" speakers and systems will help ameliorate this sensation, by adding in all the harmonic over and undertones that, even though we may not "hear" them conciously, produce a "smoothness" to the sounds we do hear.
This and these physical differences, coupled with significantly different systems and rooms, make advice of others a truly "risky" business.
I have been in listening sessions where my perceptions were "quite" different than some one else. And their's different than someone else.
What does this mean? Is someone "deaf" if they can't hear what you hear? Of course not. They just have different hearing abilities, listening preferences and listening skills.
While it might seem that "Super Hearing" might be preferable, many times it is so sensitive that it cannot be enjoyed. Women are a good example. We may be listening to something that sonds so good we have to get our wife or girlfriend to hear it and they think it sounds like fingernails on a chalkboard.
The secret is to hone you listening skills within your abilities, and design and assemble your room and system to "YOU". If you are doing it to impress your friends, you may not succeed, since they don't share your same listening asset combo.
But to answer your question, I think full range systems will sound better than limited range, to those who have limited hearing because some of the things we don't (or can't) hear affect some of the things we do.