I would separate the coastal provinces from the interior ones to give proper strategic depth and represent the separation between coastal city dwellers and the semi-nomadic and nomadic peoples on the interior. I think the region could also use a boost to its development (the rest of the MENA could too).
Hmmmm... this sound exactly like my criticism of the pre-HF CK2 map of Maghreb, but looking at the CK3 map... as much as I know the region from my 15+ years long studies, the provinces do represent the area very well. The coastal provinces do only cover the coast and don't go deep inland than their immediate hinterland. Inland provinces are as dense as it makes historical sense and with great many baronies.
So maybe could you really be little more concrete on what is wrong?
Would you be able to draw your better suggestions maybe? For instance here you have a map of Maghrebi medieval regions and settlements...it should have all historically relevant places and regions... so maybe you can draw your better setup there?
With this in mind and considering the distribution of Berber times during the medieval period, I don't think there is much to add or change, but I'm really interested to see what you think could be done to improve it.
As for development - Ifrikiya region was relatively on par with Anatolia (or very slightly ahead) in terms of wealth and agricultural output before the 11th century and I think the game reflects it. In the 11th century it declined due to natural conditions and partly due to Hilalian migration (AKA invasion). And the great city of Kairouan and its environs were nowhere near its former greatness after its destruction of 1057.
Other parts of the Maghreb had well into the 12th century only several major urban centers (Fes, Sijilmasa, from 1070 on also Marrakesh) and even the agricultural parts of Maghreb al-Aqsa (the Tamasna region) lacked major urban centers (=> high level of development). The inland had great urban centers in Tilimsan and Tiaret (AKA Tlemcen and Tahert), and there were numerous minor urban centers in the Zab and Hodna regions... which the game map does reflect.
In general I can imagine the region's development to be increased by 1-2, but nothing drastic is IMHO necessary.... I don't think that the development of the nomadic or semi-nomadic areas should be any higher.
The area in general is among the more developed areas in the world, last time I checked it was better than Europe (although I do agree the difference could be slightly higher).
The only thing that strikes me is the exceptionally high development of India compared to the Middle East - I don't think India was that much more developed than MENA, but I need to say that I know virtually nothing about history of India and the very little I know does suggest that it was very developed.