You're certainly on point when you say that ultralight design is all about making the right tradeoffs to achieve a coherent solution to a specific goal.
And I think you've nailed it with this design for the typical North American scenario. For the weight, I can't think of a solution that would give better ease of entry, views, venting, ease of pitching, efficient footprint, generous vestibules with safe cooking and drip protection, and decent performance in moderate foul weather. It really does look a well rounded design, with no obvious drawbacks given its target niche. To go any lighter, you've going to have to give up a lot of livability and/or move up to a much higher price point.
Then it's all about understanding the materials and getting the detail right. And you've clearly obsessed over that, with the excellent cut, reinforcements and guying. I suspect we've both been reading the same threads on BPL - it really is a priceless source for this kind of detail...
With ultralight A-frames, two of the main players have taken the North American approach of the short fly (Yama and HMG). So that's a non-starter for northern Europe, for reasons we agree on.
There's some nice touches in the Yama, and people say that the build quality is miraculous, but there's just too much I couldn't live with for my application .
I'm not surprised that you didn't get on with the Echo - to me it looks like a case study in making the wrong compromises and ending up with an incoherent solution. It tries to do everything, and ends up doing nothing very well. The removable beak looks like a dogs dinner - I really wouldn't like to erect that in a wind. It also looks flappy and failure-prone. And all for what - to give you the option to save a handful of grams and go out with a beakless shaped tarp that's too small for any serious application? In bad weather you want a bombproof tail into the wind, but they've left it open with very little overhang, relying on the inner for protection. Again, this is going to be draughty, flappy, and you're vulnerable to driven rain, dust and spindrift. And the dimensions are odd - I suspect that it's more to do with economising on fabric than with functionality. When I contacted them about performance in the wind they were evasive - I don't think it would do well. But it looks cool, so that's all right then. It seems that there are people who are prepared to pay $600 for this, but I really can't see why.
The BD Beta Light/ MSR Twin Sisters "double mid" design is a brilliant concept and great in the wind. Skurka took one to Iceland, which says a lot. But you've still got the mid problem of poles in the living space and awkward vestibules, so it's not an efficient footprint and doesn't play well with bug nets. I played around with dimensions that would move the poles farther apart and give a better living space but it doesn't work - it's a concept with its own inexorable logic.
The TT Protrail is a decent effort, but not really designed for wind, with it's rather odd blunt-nosed vestibule and unsupported side panels. I'm not really a fan of the all-in-one single wall solutions - I prefer a tarp so you can vary the pitch and choose a groundsheet, bivy or nest to match the conditions. The double wall concept of the X-Mid scores well here.
And finally, Kifaru nearly get it right with their ParaTarp and SuperTarp. The wind performance is there, and I like the radical simplicity of the design. But the dimensions are very odd - the ParaTarp is is so small you have to sleep on one side of the poles, and the SuperTarp is HUGE. They have mucked up the detachable vestibule IMHO, and they use a horribly saggy form of nylon. With the new silpolys, we really shouldn't have to put up with this kind of thing:
So for people drawn to an ultralight alpine A-frame, there is scope for a meaningful MYOG project that will offer significant improvements on the commercial offerings.
For the transverse ridge, though, it's hard to see past the X-Mid. So far I really can't see any potential for significant improvements, and I've been trying! Congratulations on a great design - the passion and care really shine through.