For me I think the story is going to have to be; Build my entire mod as an .esp, and convert it to .esm at certain points to verify that everything works as an .esm. I am able to create and balance my NavMeshing just fine in the .esp, though it will cause problems with NPC following through doors as you have clearly discovered. But for creating a mod that focuses on level design, my hope is that I can work in the .esp until its time to seriously test and release it as an .esm.
I will keep my master copy of the mod as a .esp, and convert to .esm for testing/releases if I can do that without problems.
Will that strategy work?
M
My newblike thoughts are...
I think it should, but remmeber that your .esm will load high in the load order. That means that if somebody's .esp farts in the general direction of the resources that your mod changes, it's gonna lose the fight with the other mod and get overridden.
If anything gets changed in your mod that it's possible that some other mod may conflict with, you might wanna load that part into an .esp so that the user can make that part load low if necessary.
btw
that navmesh .esp problem isnt a following-through-door problem. NPCs standing around in the cell are affected, too, and you do not have to have them walk through the door with you. I saw this many, many times.
My PQ01 quest originally had the player going into the huge, 1900+ triangle navmeshed cell for the first time alone. He was going in to kill a single enemy that had been placed in the cell.
If he walked in alone, then walked back out, then walked back in again, the enemy's pathfinding would be fried. The navmesh, in its brain, was gone. It couldn't follow its patrol marker pattern like that, it would stand helplessly.
If he walked in with a fresh-start game (navmesh would work), killed the thing, then walked out, collected his followers, and walked back in, the followers' pathfinding would fry.
if the teleporting-door would fail as they tried to follow me into the cell that second time, the followers would be left standing in the Wasteland cell, with the door in front of them, with their brains still fried (that cell had a modified navmesh too).
It acts like the game takes the .esp-added navmeshes and tosses them down the toilet, and the brains of alll the NPCs in the cell go with it.
......