For those who are interested, here is the article I wrote on how to design Cyrillic letters Њ, Љ, Ћ, and Ђ. https://tinyurl.com/vh9dg8g
Initially, I took these notes about three years ago when I made a research on this topic—in order to respond to the request of my friend who asked me to review the Cyrillic set of his font. I complemented the findings during the design of my font Naslof last year.
Also, in the heavier weight, bowls of Њ, Љ feel a bit funky / disruptive, but maybe Igor could confirm that as native speaker.
to my eyes, it does not feel native... you could keep the upward curve, but the stroke modulation does not feel right. Have you consulted with locl type designers?
I have a slightly different take on this. Contrast is contrast, and it doesn't really matter whether the contrast is high or low: what matters is where the thick and thin fall relative to each other. There can always be room for experimentation, innovation, and freedom, oc fourse, but these things need careful craft as much as convention, tradition, and restraint do.
I do find Christian's Л a bit strange because so much weight is being added in the descending stroke, which then tapers out towards the upturned tip. The sag on the underside of these strokes is good (a lot of people make the turn into the terminal too sudden), but there's so much weight above it, and so little in the terminal. The logic of where the thin and thick fall doesn't change because the design is low contrast.
Be cautious of comparing Л and Я as 'related glyphs'. They can be related, but when that happens — more often in the lowercase and most often in italics — it is because the Я takes the contrast pattern of the Л, not the other way around.
There are other letters that could inform the features of Л and л. At the moment the terminal looks like the flipped Latin LC t, and alien to other key letters.
Also, I find that the right diagonal of Ucyr too heavy compared the Latin V and Y. And its tail could (not should) be informed by LC Latin y.
For example, I think that the first "Hockey Club" shape could be fine sometimes if crafted carefully, and with the consideration that it could be too close to letter П. If these things are taken into account, it could work, especially for geometry fonts (though I still prefer classic sloping variant). That shape is natural in handwriting, and if you would ask people in Serbia to write the letter in the sand (skeleton) most of them would probably draw a shape like that. Maybe the perception of the default is different in Russia, someone could comment.
But this "Hockey Club" shape influenced my design, because I like to have left stroke of the Л starting with the straight segment.
I don't know what the /nine/ and /j/ are doing there
I like it this way
Consult with type designers with a native language that uses Cyrillic would be the easiest IMO. But the matter is not how you construct this or that letter but to have the eye to recognize which part is getting heavier, which one clogged, which one too anemic and so on. For example, I was taught as a greenhorn that I should push the top left oval of the Я a bit to the right. But when you realize that this is done to compensate for other parts and for it to not appear falling to the left, and that with a different shape different treatment should be used, you train yourself to do any national script. I used the same principles for Latin and Cyrillic that I used for Cherokee and I would use for Lao if I made Lao. Doing this, you also remember that sometimes a lettershape has to not only comply with basic rules, but also technicalities like interpolating the font or matching the Latin or some other script.
In the end, you are making functional art - it should feel, work and look good. This or that part can be discussed ad infinitum.