Just started a little ago, I am a vassal of swadians now. What pissed me off was; I have been granted the fief of nomar when I swear allegiance to harlaus. Then I suddenly find myself in a faction at war with 3 factions at once. Rhodoks seized the opportunity and took dhirim, nords on the other hand - no matter how a hard time I give to them - saw the opportunity and took uxkhal; so my village nomar too occasionally. Then suddenly the thing happened and harlaus signed truce with all of the enemy factions and I became fiefless lord. This took about 3-4 weeks and no matter how many times I told harlaus to declare war (to retake our lands) he ignored me. Bah! What a bastard!
Then suddenly one of the warmonger lords told me to start a war with an enemy faction, I saw the opportunity and attacked their caravans straight away

Now we retake uxkhal and the surrounding villages back. I have been granted my village back, along with another extra village. Yay!
So in conclusion, swadians are powerful. Fielding very strong knights, and sniper longbowmen they easily dominated somehow lightly armored nords. They have very strong military strength combining english longbowmen and french knights, but there is one word; they are strategy idiots! Their position is also the most hardest, and they simply can't overcome it. They supposedly the richer cities. Though they mean nothing when they can't keep them. If without my efforts, the swadians would most likely to have only suno and praven.
On the other hand, Nords are most likely the weakest faction. I joined many swadian sieges against nords (3-4 sieges) and they could not even keep their cities; the place they are the most strongest. Their infantry are bunching up together well against infantry, so cavalry attacks are mostly fruitless at the beginning. But that is all. They lack good archers, they have no cavalry at all. So they a highly stationary force, which is archer food. When they are outnumbered, even my lighty infantry was dominating them. Not to mention once their infantry bunch is halved, they became much more susceptible to cavalry charges. Not that they are that good against a well hammer and anvil tactic anyway; used with [infantry + repeated heavy cavalry charge from flanks]
I believe most of the things on the worldmap are random to a basis, though there are certain factors effecting them such as swadians' central ground weakness, khergits marching speed, etc.
However, things are still not that easy to determine. Some factions are strong military-wise, some are strong campaign-wise. There are a couple of elements deciding their strength. In my games, vaegirs often use a peaceful strategy, and keep themselves in their snowy homeland. This grants them to not engage war on many frontiers, while the other factions are weakening the others; they maintain their strength. Though this strategy sometimes do not pay that well, as one faction becames very strong with all those conquering; so they can't stand against such a foe.
All in all my ranking campign-wise is:
-Rhodoks, Sarranids (Rhodoks are doing always well and sarranids are mostly dominating the khergit somehow)
-Khergits, Vaegirs (Khergits can do well in early game, vaegirs are in the middle ground too due to their defensive strategy)
-Nords (I don't reckon nords as a formidable foe. They can actually do well, but their lack of proper military strength draws them down in my opinion)
-Swadians (they are the idiots of calradia when it comes down to campaign strategies, and are given the hardest position)
Military wise:
I think I still need to play this mod a bit longer. So far; I have only seen swadian and nord armies, and of course some bandits.
