Most forgiving high end speaker 10k-20k?

Honest1 - As a Daedalus Ulysses owner, I'd bet that the Daedalus speakers you auditioned where not properly broken in. I've had my Ulysses for about 4 months now, and initially, I was ready to give up on them... but armed with good advise from fellow Audiogoner "Raquel", I put my Ulysses thru a formal & regimented break-in process for approx. 200 hours. The break-in process was a PIA, but now the brightness & fatigue you referenced is gone and they are making beautiful music.

BTW, my previous speaker prior to the Ulysses were Harbeth M-40.1's. Another great and very forgiving speaker... more forgiving that the Daedalus Ulysses IME, but also a bit darker in presentation. Both outstanding speakers, just different flavors. I could be happy with either one.

Detail can't happen without accuracy.

Accuracy can be pretty or ugly.

An accurate image of a pretty girl is pretty.

An accurate image of Medusa ain't so pretty.

What happens to the pretty girl if you apply the same tweaks necessary to make Medusa presentable?

So clearly accuracy and detail is desirable but still can be a double edged sword. Recordings are what they are. They typically range from mostly good to not so good, but few worth listening to are the audio Medusa, ie few have no sonic merit at all.

There is an up and down side to almost everything.

Don't have the experience to comment on all (or even most) of the suggestions – but I did in fact seek to answer that very question myself, and ended up with the Verity Parsifals. Lesser recordings sound great. Exquisite recordings sound exquisite. But, certainly and overlooking upstream electronics for the moment, room interaction is likely the single most important factor regarding how any given speaker will sound at any given moment. So, considering speakers in the abstract – apart from the "ecosystem" in which they will be asked to perform – is likely not capturing much of what is material to the question.

Just as an example, my listening space is pretty confined, has a nasty (and unfortunately untreatable) first reflection point on one speaker, but an open room on the other (so pronounced asymmetry), and a limited ability to pull them too far off of the front wall. Thus, the Parsifals "fit" in my space better than many: adjustable front- or rear-firing bass modules gives fantastic flexibility and the heavily-loaded midrange driver (providing the lush and wonderful midrange for which they are known) is wired to roll off naturally without imposed crossover points resulting in a relatively "beamy" presentation. That is, the dispersion pattern coming off the midrange is relatively narrow. This may be a huge disadvantage in some spaces, but where first order reflection points are a real issue, it is very helpful. Finally, they're real small. As much as I'd love to play with the likes of Avalon, Maggies, Wisdoms, etc., just plain don’t have the real estate. Thus, even before hearing them, their design rendered them an almost-ideal prospective “fit” for my space.

In sum, I wouldn’t purport to have The Answer – and there likely isn’t one – but there are certainly many factors to consider. I’ve settled on my answer, but certainly not one size fits all.

I have found that, in general, I prefer speakers with soft dome tweeters. To my ears, when they are properly fed, I am less likely to be bothered by them and can enjoy lesser quality recordings vs. other tweeter types. That and a good supported bottom end also contributes to less fatigue for me. This is probably why I prefer the sound of Eggleston speakers. Are they the most revealing? No. But to my ears they are very musically engaging and highly satisfying.

I don't know what went wrong with the Daedalus speakers I heard. I was very surprised to hear tehm sound that way, and disappointed that the search would have ot continue. I do remember that they did not have the crossover upgrade to the capacitors (the owner was going to have that done). Who knows - bad cable match?
I second Rockadanny's Eggleston recdommendation. I heard them briefly at CES, and found them to be fairly resolving and very non-fatiguing. I considered them as an alternative to Ascendo, but never got around to doing a comparison in home.