Klipschorns

How close were you seated to them? Old horn styles require 15 feet @ least, from my experience with them years ago, in order for them to sound right. Even 20-25 feet was not an uncommon listening distance, where I grew up in the Midwest, for nice sounding residential horn systems. Many of these speakers were also used in bars, meeting halls/auditoriums and movie theaters with huge rooms. I did not pay much attention to the "size" of the sound back then, but did acknowledge a more seemless presentation as the listening distance increased (it just sounded a lot better, more like music and less like speakers, even to a kid). Hard to guess as to what your listening room did to the sound as they are so variable.

I knew someone that bought a pair. He hated them. Returned after a week.

my brothers both owned Klipsch KG 5.5s and though they sounded good (in HT IMO) I never thought they gave a true to life performance for music. Too bright IMO.

While I'm not even close to believing that Klipsch's are the best ever made (of course they're not) they are still a pretty good speaker & I wouldn't trade mine for anything except maybe even better horns such as the Avantgarde's. I love the dynamics of horns; mine stage quite well & have a natural sound that cone speakers haven't provided in my room; so your experiences I believe were setup related. These speakers are SO very sensitive & revealing that if the source & setup isn't good then you will definitely know about it. I experienced none of your complaints, & you are correct in that synergy is the secret to getting them to really deliver.
So many people talk about mating horns with tubes, & in fact these classic designs were made back when tubes were the only gamne in town. However I've tried driving them with many different components & my best results are with mosfet amps. Perreaux works quite well, as does Ayre Acoustics, McCormack, Monarchy, classic Luxman, & of course Accuphase. A very quiet tube preamp such as a Golden Tube SEP2 or SEP3 works very nicely driving a solid state mosfet amp. Another quiet one is the AMC 1070s Tube Preamp. A number of other expensive & highly regarded tube pre's were revealed by the horns as so noisy & microphonic as to be unbearable. Right now I also have an Accuphase pre (solid state) & the combo is magic.
Cabling synergy is also very important, again I suppose due to the sensitive & revealing nature of these horns. MIT speaker cable does a real nice job for me, the MH750 Magnum biwire. Interconnects, AC cords, line conditioning, clean source components, tweaks: all are critical. It's a lot of fussing around to get it right but when you do get there it's just amazing. Up to you if it's worth the hassle; it is for me.