openmw.org

Portal one was made by Valve as far as I know

No, it wasn't. Well, not from the very start, at least. Ever heard of Narbacular Drop?

A nice workaround for now would be to add a "Hours played" feature to the engine. AFAIK, it already records the time played into the save file. So, it's just a matter of reading that value and showing it in the UI, am I correct?

I don't think so, no. OpenMW offers the same mod installing experience out of the box (multiple data folders), why would you need NMM? The only thing that comes to mind is user interface. Well, if you really need it, there are already some CLI mod managers for OpenMW out there, like this one or that...

I don't recommend using MGSO with OpenMW. I don't recommend installing it at all, actually, as it is too outdated and contains tons of bugs. You're better off installing mods on your own, this way you can test if they are compatible with the engine or not. Like Zacharon did . And I'm repeating for t...

You can install Tamriel Rebuilt the OpenMW way.

No OpenMW + MGE (XE), ever*. Tamriel Rebuilt works nicely, though. MGSO is a huge mix of mods, so can't really say for sure. MGE, which comes with MGSO, definitely is not compatible as aforementioned. All of the texture replacers should be fine, as long as they don't use fake bump mapping. Concernin...

Not a fan of the noise

Same here. Don't like the noise and especially grain effects in games (I always turn them off).

Or simply use Chocolatey.

He didn't say he uses MCP (can you even do that with openmw.exe?), he only mentioned the corresponding MCP features that could be incorporated into the engine post-1.0

Also, it came out a year later.

They were both released in 2002. But I guess you're right about rushing and open world vs not open world.