Because the campaign maps are tied to DLC more than anything, which is also why Prithviraj has not been moved to the South Asian bookmark.
For the record, I would like the bookmarks to be changed entirely because I also don’t like much how things are currently done. I would probably do it this way:
- Western Europe: William Wallace, Joan of Arc, Barbarossa, Edward Longshanks, the Grand Dukes of the West
- Iberia: El Cid, Tariq ibn Ziya, Francisco de Almeida
- Italy: Alaric, Bari, Sforza, the Hauteville
- Eastern Europe: Dracula, Ivaylo, Aldrigas and Kestutis, Jadwiga, Jan Zizka
- the Steppe: Genghis Khan, Attila the Hun, Tamerlane, Kotyan Khan
- South Asia: Prithviraj, Babur, Rajendra, Devapala
- South East Asia: Gajah Mada, Suryavarman, Bayinnaung, Le Loi
- Africa: Saladin, Soundjata, Yodit
- Americas: Montezuma, Pachacuti
It is relatively balanced, with 3 to 5 campaigns on each map excepted in the underrepresented Americas. It is obviously not perfect because some campaigns take place in several theater and there will always be debates about where the lines between those areas should be drawn, for instance Saladin should arguably be placed in a Middle East map but then he would be all alone (which is sad).