Sure except that reading between the lines requires historical parallels and the closest I can view to the Dothraki are the Mediterranean pirates who once dominated the entire sea (during the Roman Republic's height). Was it because the Roman Republic really couldn't deal with these pirates? Clearly not seeing as Pompey destroyed them all in a naval campaign the moment they made the mistake of sacking a Roman town. Why were they allowed to exist? Economics and because there were multiple strands of politics that made them useful to the Republic.
As for the trade network, well yes. They are an important component in Essos trade however there's a bigger reason why they're allowed to hold the territory they do. The most prominent Yi-Ti to Westeros trade route happens to be maritime in nature as well as in the control of Qarth, New Ghis and then Volantis (three powerful states all of whom have a lot of incentive to ensure that a land route from Yi Ti to Qohor never exists).
Qarth: Separated by the Red Waste and can't expand in Dothraki territory anyway.
New Ghis: Hemmed by mountains and rivals with Meereen so they're never going to allow Meereen to get too strong and expand north with border fortresses.
Volantis: Likely trying to but has tons of problems with actually holding this huge slice of territory in the northeast (for other problems that the Volantis player will be made aware of).
But all of them would have a massive freakout if they found out Qohor was actually making enough deals with various Dothraki Khals to make a Yi Ti-Qohor land trade route viable and thus dodging all three. Qarth in particular has an assassin's guild and isn't above knocking off certain Khals and maybe trading certain weapons to Khals who aren't willing to allow Steel Road to ever be used since their entire economic dominance is built on it's lock over the Jade Gate trade route.
It's really not. Canon Braavos actually exports iron and timber. Norvos and Qohor all have iron resources as well. Volantis interestingly does not, one of the many many factors that keeps them down.
-Armor very much is an Essos thing.
I'll be completely honest, this is a pet peeve of mine to view certain areas (Iron Islands, Essos and so forth as simply incompetent), so I'll just outright say this isn't how I intend to mod Essos. Essos has problems and as I told my three Essos players in college, expect it to be an uphill battle but expect to have challenges and rewards that make them as fun to play as Westeros. This is a continent that has successfully and very quickly been able to form coalitions to ensure balance of power whenever need be. It's also an area that historically contained the Rhoynar Empire that raised 250,000 men. Even if I assume that a lot of that was due to culture (women and men both fighting) and enormous amounts of irrigation projects due to Rhoynar water magic, Essos is very much a rich area and underdeveloped area (seeing as Tyrion didn't see anyone settlements along the Rhoyne river). Anyone who chooses a Free City can expect my private missive to them to explain what is particularly problematic for them and what's the major issues they face (why for example is Qohor which raised 30,000 soldiers under Aurion is now such a light-weight?). Similarly, the Dothraki and Iron Islands player would get a missive explaining things as well.
Now what are the general problems an Essos city-state faces?
1. Difficulty of genuine expansion
-If the Essosi "play at war" it's for a very good reason. There's no point in investing in a very strong military when all the Free Cities are sophisticated political actors that are never going to allow the balance of power to shift and put their own independence at risk.
-Volantis knows for a fact that they are never going to be allowed to occupy Lys (the City-state) without causing a counter-coalition to form against them.
-The primary fights are over border territories that come in and out but since you know you'll never be able to permanently knock out a rival without intervention from other Free Cities there's little point in trashing your economy for impermanent gains (most wars are minor and over trade rights and generally limited in scale because actually conquering another Free City is a red line the other Free Cities will react to).
-Does that mean a clever player wouldn't be able to manipulate the balance of power to expand? Of course not, but it's something to consider.
2. Slave Society vs. Society that Just Happens to Have Slaves
-A slave society paints all activity in a certain light and becomes a fixture of the culture. Just like how in Volantis, it's considered "slave-like" to even walk in the streets, Essos has a mobilization problem based on culture.
-The fact that even though Volantis in the books is having a problem with a potential Pro-Danaerys slave revolt and yet they've been unable to create a Freemen Army by sweeping up the Freemen beggars who still consider themselves better then slaves should give a good idea of how much the slave system has made a distinction between:
Manual Labor = Slavery [and]
Intellectual Work (Merchant work) = Freedom
This is an enormous problem to overcome but Free City players have a rich city and the countryside population that is necessary to sustain said city.
3. Republican Government
-This is actually the potentially biggest potential problem hemming the Free Cities in. In short, even if you do manage to convince Freemen to serve in the armies you now have the problem of actually using them.
-Volantis' Tigers fought enormous wars but failed to realize that with each soldier that died, so did their base of support and ended up dooming themselves to centuries of political isolation.
-Similarly, the reason why an Essos Free City Player has to be cautious is because in all likelihood, if they're building up an army, all of those newly paid soldiers are likely going to cast their vote for you and every one of them that dies happens to weaken your political platform.
-This: Is the single biggest reason for the widespread use of mercenaries in Essos. In Westeros, a lord could shove his entire peasant population to their deaths and he will remain lord. In Essos, the clever politician will use his Free City army to garrison territory but would probably weep to see his Pro-Magister Army get decimated in battle [and] since you have the wealth to do otherwise, why not use mercenaries?
Now then, I'm going to have to go offline to finish my work so I won't be able to respond more
. That said, when I begin the OOC thread I can assure everyone regardless of what faction you choose, you're choosing a political entity that has survived more or less for hundreds of years for a reason. Even the weakest faction such as Lorath has a reason why they haven't been annexed which will be explained in their secret missive.
-The problem with assuming incompetence is simply because in the hands of intelligent players (and I had to deal with many) is that they will automatically exploit weaknesses in GRRM's narrative overly easily.
Ex. if I assume Essos' Free Cities are incompetent, the basic problem is:
1. Why hasn't Dorne expanded Eastward? They could arguably take the Stepstones and/or Tyrosh.
2. Why hasn't the very religious Arryns not taken Andalos? Their literal holy place and ancestral homeland of the Andals.
3. Why hasn't the Iron Throne ever directed it's attention outwards in order to create a release value for landless knights and population issue.
Similarly:
1. Why haven't the Ironborn been exterminated?
2. Why has the Iron Throne never allowed Lord Harroway's Town or Maidenpool to gain a charter? Was House Tully really so incompetent that they never asked?
