There are a few videos on YouTube of people showing heavily modded Daggerfall, and it looks pretty great. It seems to have been embraced by a dedicated community of modders who provide full instructions of how to get it all set up how they have it.

Here’s one sample video of what people have accomplished.

I've completed several playthroughs of Morrowind on OpenMW, and I've found it to be superior to the original engine in every way. The only thing that you might have issues with is certain mods may not be compatible with it, but I don't really use mods.

Daggerfall's a huge game, but it gives you a ton of freedom in how you play. Once you figure out the basics, it's a great dungeon diving experience. Although the procedurally generated dungeons aren't everyone's cup of tea, since they can get pretty crazy sometimes. I would highly recommend a teleportation spell (mark/recall all-in-one).

Yep, OpenMW is totally playable. There's also a multiplayer-enabled version of it around, which works surprisingly well.