Not to rain on your parade, because enthusiasm for making OpenMW better is certainly always appreciated, but this may be a bit premature. I am not a dev, so feel free to take everything I say with a grain of salt, but at this stage, I think the best way to make OpenOB happen is to help OpenMW reach 1.0 and get dehardcoded. Oblivion's mechanics are by and large similar to Morrowind's, and much of these could be fairly easily taken care of post-dehardcoding by just tweaking some of the attributes/skills and how they work. Roadmap-wise, this is also when the project will be much more open to merging significantly new features. Let me share some more of my thoughts on this by answering your questions.
Roncon wrote: ↑
23 Jan 2019, 00:05
I guess my starting question is, is there any sort of roadmap for this? Are there any issues with the current version of OpenMW that need to be fixed before work can start? Is there a known group of developers already working on this?
No. Yes. And kind of. Implementing Oblivion in OpenMW is not part of any of the project's official goals/existing roadmap. That is not to say it has never been discussed, as obviously it has, but supporting Oblivion is so far removed from our current set of goals, it has not seriously been thought through by the main devs as far as I know.
This implies that there are in fact significant issues with the current version. Devs would be better able to answer this in a refined way, but basically, if we can't play and mod Morrowind yet, then we obviously can't do that with Oblivion.
The only known devs working on this would be cc9cii, and he isn't exactly one of the main devs of OpenMW as far as I know (not that his work isn't great).
In terms of roadmap, generally we have a few milestones. First, full reimplementation of Morrowind and a fully functional CS are our 1.0 goalposts. This is significant because we can't really make most of the proper post-1.0 advancements until the CS is working enough to take advantage of them. Immediate post-1.0 is laid out in Zini's design document
(linked for your viewing pleasure). General goals for post-1.0 include dehardcoding, so that more of the basic mechanics can be easily and fundamentally changed by modders, and adding a scripting language, so that modders can access more of the engine's inner workings for more powerful and stable scripts. A probable goal that has been mentioned for the 2.0 milestone is to merge TES3MP into the main codebase.
As you state that one of your eventual goals for OpenOB is to utilize TES3MP, it seems prudent to hold off on some of this until the 2.0 mark happens. Admittedly this is far far into the future, so it may not be realistic to wait that long, but I have a few more thoughts in response to the next bit.
Roncon wrote: ↑
23 Jan 2019, 00:05
I am, of course, very new to the codebase and architecture of OpenMW, and as such I don't expect to begin contributing right away, but with a clear roadmap it becomes a lot easier to breakdown things into small tasks that even a beginner can start looking into. After that it's just trial and error and lots of feedback from more seasoned developers.
Enough people are excited about Oblivion in OpenMW that waiting until post-2.0 is probably not realistic or entirely necessary, that just makes merging with multiplayer functionality potentially smoother. However, many parts of the Oblivion engine are things many of us would like to see in OpenMW. Real-time ragdoll physics, "radiant"-AI, skill perks at level-up, horses/mounts, character model customization, an actor voicing system, are all things that would be fun to implement in OpenMW as we move closer to the goal of being a general purpose engine. As you are not familiar with the code base, working on current OpenMW goals would put you in a much better place for eventually focusing on one of these once the time arises. I see no reason why most of these wouldn't be enthusiastically merged post-1.0, and keeping future TES titles in mind while developing these I think would generally be regarded as a smart move.
There are some other thoughts I have about some of the more difficult to reconcile features of Oblivion and Morrowind as well as trying to load Skyrim into OpenMW, but I'll wait for them to be brought up before discussing further. This should hopefully help you get an idea of where things stand.