Why is it wrong, i stated an argument, please return the favour.
You can have two altKeys and still have plenty ways to produce AltGr mappings.
Actually, as has been explained to you many many times before, there are ONLY two maps for Alt. Left Alt and Right Alt. When AltGr is activated, Right Alt BECOMES AltGr. There isn't BOTH. There are two, and will only ever be two, Alt keys. You cannot proclaim that there are 4 (Two Alt and two AltGr). They simply do not exist that way.
2 dedicated keys, one too little to be usable for anyone
Thanks, but I and others can find lots of uses for this keyboard. You have not defined what 'too little to be usable' by YOU is, but simply stated a broad attack with a claim of utter unusability.
swappable dedicated keys, having to Fn+L to do so, or learn where brackets go if you need them
(non-dedicated ä confused with backspace )
I'm sorry, but I fail to see what Fn+L has to do with anything here. No learning, 'where brackets go'. They're explicitly mapped on the bottom row. The non-dediated Ü, being on the Fn layer may take some getting used to, but it is clearly marked and functional. I'm not sure why you're going on about ä though.
No language layer, 3 named letters
The entire keyboard is a polylingual layout. It is not necessary to change definitions for one language or another. There are actually 38 named letters on the keyboard and direct diacritic support for dozens more.
Not confused with AltGr a bit. It simply negates the need to activate AltGr (and loose the right Alt key) for the entire language sets of Western Europe. AltGr CAN still be activated IFF the end user chooses to do so. In the vast majority of cases, though, it should not be necessary.
5 available keys with Fn, out of total of 47 possible
Please list the key symbols that you think cannot be made using this layout. Or did you mean that there are only 5 that do not have something already mapped to Fn? You're a bit vague on this one. Anyway, you're making a statement as a 'negative' without explaining WHY it's a negative. There is nothing wrong with utilizing the Fn layer. As you have noted, it is not possible to do a proper keyboard on the Pyra without using the Fn layer.
By having dedicated language keys on the top and Fn layers, the actual need for someone to use Compose is negated in nearly all 'normal' usages. It's still present for those odd cases when it's needed. Quite frankly, though, on this layout and most of the others here, compose won't be needed often as they have more solid polylingual support 'out of the box'.
5 US diactrics that are marked
Look again. There are 10 marked diacritics on the Fn and Fn+Shift layers of these keys: ,< .> /? '" `~They are marked win an unobstructive dotted circle in the alternate (orange) color. Easy to find, easy to use, properly marked for convenience.
Azerty (and others) not possible
I'm struggling to find relevance to that. It's a QWERTY keyboard with added polylingual support. The only way yours or any layout can become 'AZERTY' is by cutting up keys and moving them OR re-mapping and remembering. Either are as possible with this as with any other.
Dvorak and NEO not possible
Again, how is this remotely relevant? A proper Dvorak Simplified layout requires 14 keys on each of the top 2 rows. We have 11 and 12.
You and Saber seem to be lashing out in this process. It isn't helping, it isn't getting us closer to something for everyone.
I'm trying to answer questions where possible on the subjects I'm familiar with. There is no necessity for you to attack someone else's layouts to answer questions about or, "defend your own."
This isn't us Vs them. This is us trying to find what works best for most and inconveniences the least while realizing that no one solution is going to be golden/perfect for every single person's every single need.