Ok, so I have some thoughts about Tarkir's world-building that you may find interesting.
A lot of the cultures on Tarkir feel weird. While they have real-world inspirations, they aren't necessarily logical mirrors of their counterparts. Specifically:
1. The Abzan are supposed to be inspired by the Ottoman Empire... so why do they feel nothing like the Ottomans? While they may be masters of
Siegecraft, that's really the only similarity. The Abzan is a nation of loosely-aligned clans huddling in desert citadels. They are a far cry from the masters of the eastern Mediterranean, with a capital in the City of the World's Desire like their inspiration.
2. Why are the Temur called "The Temur Frontier?" Is that supposed to be the name of the land the clan inhabits, or something else? The word "Frontier" implies an unsettled border region, not the home of a civilization. Is it an exonym?
3. The Sultai are supposed to be based on the Khmer Empire, but they feel more like a Northern Indian culture. Why? Likewise, did the Sultai actually build their monumental architecture? Their cities seem to be overgrown and falling into increasing disrepair. Despite the hordes of zombie servants to potentially keep things kept in shape, the Sultai seem content to let their cities decay. It's almost like they're occupying a kingdom built by someone else... put a pin in this one.
4. The Mardu Horde are supposed to be the Mongol Empire, but they feel like a tiny clan. They don't have any cities, or even anything resembling a structure. I guess we see a couple of tents that may belong to the Mardu in the Fate Reforged printing of
Windscarred Crag, but that's about it. I don't think these people are an Empire; I think they're barely getting by.
5. The Jeskai seem pretty cool, and certainly the most coherent of the Clans from a flavor standpoint. Mystic Monks living in the Mountains. Cool. Their Monasteries are kept in shape, they seem to have a fair level of organization, and everything with these people makes sense... except, why do they live in the Mountains? I know this may seem silly, but if the biggest threat to the Humanoid civilizations of Tarkir was the Dragons, why build at higher altitudes closer to where the Dragons live? We know it can't be due to the cold because the main Dragon Brood antagonizing the Jeskai
has icy breath. There must be more to this than meets the eye.
So here's the thing. I think a lot of the "issues" with the clans of Tarkir could actually be explained by considering the time
before the first dragons. Tarkir is presented as a fairly "static" world, with the only major cultural differences between the distant past and the present being dictated by whether or not there are dragons. The clans are fairly similar both in the past when they are fighting the Dragons and in the present timeline where the Dragons are dead. However, draconic influences completely reshaped the clans in the timelines where the Dragons did not go extinct. I think that the world of Tarkir probably looked quite a bit different before the first Dragons arrived. Dragons are essentially natural disasters with wings, so it makes sense that their sudden introduction to the plane following the birth of Ugin as the dragon soul of Tarkir would have widespread consequences for the denizens of the plane.
So, what did Tarkir look like before the first Dragons? Here's what I think.
It all starts with the Abzan. The Abzan's inspiration, the Ottoman Empire, took on an impressive mix of titles from the various Anatolian rulers they displaced. Chief among them were Kayser-i Rûm (Ceaser of Rome) and Khan. The Abzan may have started as a small Beylik on the sandsteppe, but eventually expanded into an empire to encompass most of the plane. The Khan-Kaysers-i Tarkir would have conquered most of the habitable areas of the plane, with a few exceptions. First would be the monks of the Jeskai Way. Using mana leylines of the Highspire Mountains to their advantage, the early Jeskai were able to build impressive Monasteries, especially in the region surrounding Pearl Lake. Abzan siege beasts (including their famous Rhinos) were unable to traverse the mountains, making the fortresses virtually impenetrable. The next was the Kingdom of Gurmag. This
faction would have inhabited the swamps of Gurmag, building impressive castles with the help of awesome war elephants. The Gurmag Empire Kingdom would be safe from the Khan-Kaysers in their swampy palaces but would have to be careful in using their limited supply of White mana to ward off the demons and snake people of the swamps. The "Temur" would not exist yet. Instead, the frontier would be a series of sparsely populated colonies sanctioned by the Abzan Empire. The Mardu Horde would have been entirely unimpressive during this time period, if they existed at all. The Mardu likely would have been bands of raiders, attacking imperial colonies in the frontier in lightning-fast raids. However, core Abzan territories would have been protected by the massive citadels we see in the present.
Everything, of course, changes when the Dragons arrive. Ugin, son of the Ur-Dragon and brother to Nicol Bolas, was born to be the very embodiment of Dragons for the plane of Tarkir. After his birth, Dragon Tempests began spawning the draconic broods that would fundamentally transform Tarkir. The Abzan Empire would collapse. The once plane-wide mega-state being relegated to only a few cities behind walls bearing the names of long-forgotten Khan-Kaysers. In the chaos, the frontier settlements would be cut off from any resupply. Their fledgling cities would collapse into a series of clans, carving out just enough resources to survive the snowy, cold, wooded foothills. These people would eventually begin to call themselves "the Temur frontier." It is no coincidence that the only factions to have Ainok are the Abzan and the Temur– these two entities were one and the same in the distant past. In the Mountains, the Jeskai would largely continue as they did during the Imperial era, except now they had enemies who could actually attack the mountain monasteries they called home. Luckily, the magic that allowed the construction of their impossible monuments in the first place would serve as protection against draconic attacks in some capacity, strengthening the structures enough to keep the clan safe. The Gurmag Kingdom would not be so lucky. Silumgar and his brood of poison-breathing Dragons were perfectly suited to kill the Gurmag war elephants. The people of Gurmag would either be wiped out, or forced to submit to the Rakshasha and Naga. In either case, the great architects of Gurmag would be supplanted by
Snake-Cults and scheming
Rakshasha , the only record of their existence being slowly decaying great palaces. Finally, the Mardu would actually come out ahead in this world. It's possible that the origins of the Mardu are actually post-dragon, like the Temur: they may have been residents of Abzan cities in the plains that
didn't have great walls like the desert fortresses. However, if they existed before the rise of the Dragons, they certainly would have been able to expand in both territory, wealth, and power by scavenging Imperial cities destroyed by draconic forces. The nomadic lifestyle of the Mardu meant that they would have been able to avoid constant Dragon raids simply by never staying in the same place. It's possible that Imperial refugees may have even taken up the saddle and bow and become part of the Mardu clan as well!
In either case, the five clans would eventually begin calling their leaders "Khans," a title used to show their claim to dominion over the plane of Tarkir. Although they would not be able to act on their claim during the time of the Dragons, this would not always be the case. In the timeline where the Dragons go extinct, the Khans fight each other in an eternal war to reclaim rulership of Tarkir. Although the title of "Kayser" may have been lost, the drive for domination would remain. Unfortunately for the Abzan, their sharp decline from power during the reign of Dragons meant that they no longer had the population necessary to defeat the younger clans. They almost take the place of the Byzantine Empire or late Ottoman Empire from our world, as the "sick man of Tarkir."
In the timeline where Dragons survive and take control of the plane for themselves, the title of "Khan" too is forgotten along with it's "Kayser" counterpart, as the world slowly forgets the time of the clans and the Empire...