I know I'm a bit late for the party, but I would like to add my grain of salt on the gameplay demo.
First I would like to add a well deserved congratulations on the demo, even though it feels a bit scripted (and really, there's no reason why not to do so) there was a lot of stuff to go wrong and the game seemed very smooth. You can really see where those 4 years of development went and, as you guys don't plan on releasing it any time soon (maybe end of the year, but I would bet on first quarter of 2017) you will get a very ass kicking product by them.
Your engine feels very solid: collision seems great, the lighting effects are simply amazing and the way objects interact seem very well thought and done.
I can see some great improvements in AI also, as pointed by some of the other posters, as in the way they try to keep the correct distance to hit or how the cavalry doesn't stay still and actually tries to keep moving away from infantry, as it's how cavalry should act.
It's very understandable that you guys used the order to "charge", as people, media and general pop culture believes that medieval warfare was mosh-pit of swords, lances and arrows, but I would really like to see how 2 formations would face each other in this iteration of the series and how they would, or not, try to retain and fight in said formation. Also, if they are not there yet, it should be available to make units behave in certain well known formations (i.e. if you have 4 of leadership you can order your troops to form in horse shoe or while approaching a fortress, do so in tortoise), but that's speculation of my part.
The menus seem much more optimized, if not a bit crude, on how it present information for the player, I really like it, but I believe that if you guys aim for a more broad scope of players you maybe should try something a bit less total war-ish: warband did actually a excellent work on presenting menus in a very user-friendly way.
The last nitpicking is that, as a historical fencer myself, I felt the handling of the weapons a bit clunky, on my opinion they should be relatively faster than they are and feel more fluid. But you can still feel the hits and the movementation is quite good, feels more natural than warband and more accurate.
All in all you guys seem to have accomplished something great, which build on your past hits, but try to improve your misses. I'm really trilled to see and know more of this game