The only reason Klipsch re-issued the Heritage line is because so many people are looking for vintage equipment and are willing to pay a premium, as if that was some kind of Golden Age of Audio. Look at the Heresy- the rated frequency response is now 58-20KHZ, +/- 4dB. The original spec showed 50-17KHz, IIRC, but I don't remember if it they included +/- 3db, or 4dB- either way, that's not legendary. They sound good for some music but definitely not for all. I had someone call to ask if I could check a pair out because he thought they sounded dull- I ran pink noise through and used an RTA to see if they had any inherent issues- if 20KHz was the goal when they were designed (it wasn't), there was definitely an inherent issue- they don't do 20KHz. They did just what the label showed. The thing to remember is that they were designed in 1957 and the other equipment available at that time performed about as well as FM radio- 30Hz-15KHz, +/- 3dB with the added benefit of the design community and all of the experts thinking that was good enough. It's OK, as long as you're not comparing it with speakers that do better at both ends and the response is flatter.
I don't dislike all Klipsch, but I have never been a big fan of the Heresy.
I haven't heard a pair of the larger Klipsch speakers in a long time- they definitely had a sound that allowed them to make listening to music different from small speakers- the amount of air they move has a lot to do with it. I had a pair of Electrovoice 30 woofers and they did the same kind of thing.
WRT your comments about speakers being worse- not correct, by a long shot. Modern technology, manufacturing techniques and materials make it possible to create speakers that blow old ones out of the water.