I've finished the 5 main maps of Part I and, while I do have videos which are hopefully helpful for you, here is some feedback I can provide in retrospect (as opposed to in the heat of the moment).
Map 1) I don't recall anything negative in particular. Functioned as intended I believe and I really enjoyed the side quest as well and the challenge of possible dipping into Andorhal against all odds. I didn't, but apparently most folks do!
Map 2) I quite enjoy this one even if I completely blew it during my first playthrough. Siege footmen are the clear choice here, so it would be worthwhile to restart and change tech options if you picked something different. Apparently there is a Cursed item somewhere hanging around, so I'll have to replay and check around for it.
Map 3) Great concept, though the AI appeared broken (you've seen it). No normal enemy attacks except scripted/spawned drop on top Orange base, which happened very suddenly and with a huge enemy force. This appears to have been been corrected recently, so I'll give it another go. Losing the optional is meant to cause the zombie drops in map 4 or so I've read. I did not technically fail the optional, but still got zombies dropping on me in map 4. Perhaps this has to do with the AI issues when I played Havenshire?
Map 4) All 3 Deathknights attacked me along with the zombie drop (as mentioned above) when the timer was hitting about 19 minutes, which seemed very early relative to the difficulty of the rest of the map. After this, one DK came with an attack, then two a couple minutes later with an attack, so the progression seemed disproportionate. I would expect the ramp up of 1 > 2 > 3 DK's as the timer ticks down as opposed to 3 > 1 > 2, where that first attack with all three happens after only about 5-6 minutes of getting set up plus a zombie drop that may have been in error. To be clear, I am NOT complaining/saying this is too hard; I've noticed some random commentors around here get all uppity about that sort of thing. I'm just questioning if it was intended to be this way as compared to a typical hold out scenario ramping up in difficulty over time.
Map 5) There is an invisible wall midway through the city stopping players from traveling east prior to picking up Landgren. Adding some barricades, and/or dialogue of the troops there saying "We'll hold here, go find Landgren" would make it more seamless rather than invisible path blocking. Noth taunted me, but was missing and could not be fought. I notice earlier in the thread that the Necromancer is not meant be killed, though I did manage to kill him. Not sure if he is literally supposed to be invulnerable and only should flee at low mana, or if it's a "Don't enter Andorhal" type thing. He began taking damage after I killed the Acolytes around him and tanking with Abbendis + Landgren's shield protecting her. No drops from him either if he is indeed killable as a challenge.
Lastly, what are your thoughts on adding the Secret Mission to the mission launcher or the first person mission picker once unlocked? Currently, the only way to play it seems to be replaying map 5 and fully finishing it even if it's already been done.