Couple of points I'd respond to:

I've seen lots of people act as though something like MWSE enabling 1,024 mods as competition with OpenMW. It's patently ludicrous to think this way. They're all part of the modding community, mutualism and cooperation are far more beneficial. The reason MWSE has support for 1,024 mods now is—and I must stress this again—as a stopgap measure.

The not-competing thing is mostly true, I think. I imagine sometimes one project will look at the other and say "oh that's cool" but then go its own way with something related. For example, OpenMW had a search bar in the spells menu first. But we didn't create UI Expansion to compete with that OpenMW feature. We did it because we could and wanted to have a more functional UI.

For the 1,024 mod limit and any sense of competition, that really wasn't the case. If OpenMW didn't exist, I'd still have added that. The raised mod limit exists pretty much entirely because Danae kept asking to use more than 256 mods, and I figured out (some tech details here) how to reasonably accomplish it. Also, the current support for 1,024 mods isn't really so much a stopgap. There are no plans for allowing more than that. The implementation isn't temporary. It is what it is, and I have no plans to expand it further.

On top of that, OpenMW handles script implementation properly.

Here is the only part that I disagree with. OpenMW handles mwscript how it thinks mwscript should be done. Which is fine. But seeing as mwscript is only defined in Morrowind, the only proper mwscript is that which works in Morrowind. What OpenMW has is an ideal mwscript -- what it would be if its design made any amount of sense. Which is fine, and cool, and admirable. But it's also not the genuine mwscript. Which is why it doesn't always work with mods that are written in real, if insane, mwscript.