So does that mean that Morrowind will never have animations that are smoother like in Oblivion or more bones or physics and AI like in Crysis Warhead even if it's using the Ogre3D engine?
The idea behind OpenMW is to be able to play classical Morrowind on an updated, open-source game engine, in order to fix a lot of the irritating bugs that are still present (as well as play MW on other platforms). However, in a lot of ways, it's really an emulator - in the sense that it has to emulate the original engine. Unless they are going to ship with a mod "patch" (which is possible), they will have to replicate things like the scripting engine as perfectly as possible to keep the game from breaking. So, stuff that directly affects the core engine are going to necessarily be Morrowind-like - since breaking the vanilla game would be kind of pointless.
Which, for the purposes of your list, means that the base AI will have to be implemented pretty close to the original. It may be possible to add new packages to support new behaviors available to mods, but the current AI system will ultimately have to be supported - since a failure here could actually break the game. I would like to see AI packages that would support a true sitting/laying animation, so we could have real chairs and beds in Morrowind, but I'm not holding out for that one.
I believe more bones are already possible - I believe Axel figured out that you could possibly add at least a couple more without breaking the existing engine. A new engine could certainly support more, but it would have to do so carefully, so as to avoid breaking the vanilla game.
Animations can be smoother now - the only limitation is frame rate versus speed. However, most of the animation code is actually stored in the meshes - which means that vanilla is going to look like vanilla regardless of the engine. Scripted animations could potentially be improved, but at a great risk of breaking vanilla scripts.
Physics I don't know about, but I wouldn't get my hopes up. It's possible, but obviously it would only be fully supported in mods - the vanilla game has no concept of Havok. A lot of things that are havok'ed in Oblivion are statics in Morrowind, so I suspect this would be difficult to support very well.
What I expect out of OpenMW is an integration of stuff like MGE, MWSE, and MCP (the effects, not the code). We will likely see the game engine directly implement newer shaders out of the box, and sidestep obvious bugs and shortcuts (like rain/snow collisions, etc.) I also expect that someone will port the whole thing to OpenGL, and ultimately, Linux. It would be very nice to have Morrowind running on an Ubuntu box.
Even more exciting is the prospect is that the OpenMW team will fail to reproduce the jitter as you get further from the origin. This would mean that you could actually create all of Tamriel as a gigantic mod, and not have NPC's shaking to death in High Rock. Shoot, you could even add in the Summerset Isles and the Akaviri lands.