A few thoughts I've developed while playing the latest beta.
On sounds: I love what you have done here, they really add to the setting. Only one small complaint, the bell sfx that plays in some towns loops a bit too fast, it gets annoying rather fast. Also, no offense to the voice talents but some of the Teuton battlecries (the ones marked 03) are cringeworthy and detract from the overall experience.
I've noticed some economic balancing and I hope you continue this trend. There is a bit of a gap between mission rewards and regular expenses (equipment, wages) that renders missions largely unprofitable and necessary for the relations only. This makes the game rather tough at the start as you have to take missions to get troops, but you can't make any real profits to hold on to troops until you can start looting and taking prisoners. which you don't have the troops for.
While I love the visual variety of armors there doesn't seem to be much actual difference between them, save cost. Aside from looking better there seems to be little incentive to go from common mail armors to the ones that the commanders are wearing. I'd like to see a better progression of armor values from the lowest to the highest, with price and quality translating into effectiveness more clearly. Also because of the relative sameness of armor values coupled with the high troop stats in powerstrike and weapon skills, armor does little more than provide a slight edge in combat rather than meaningful protection. I'm not suggesting you take the RCM route, but I think some heightened protection is needed to compensate for the high troop stats.
Loving the new missions so far, while a bit obscure at times they are a breath of fresh air compared to the native quests. I would like to see some new marshal/campaign missions too, scouting and finding cattle gets a little old, raid or search and destroy missions would be interesting. Also it would be sensible if there were some kind of progression in missions according to your renown and relations and vassal status, after all I doubt that lords would ask their peers to go round up cattle or fetch horses for them, though they are entirely appropriate for a lowborn mercenary.