I like U9's style and atmosphere and general gameplay concept, but I'm not big on the execution. What games are similar, but better executed? Gothic comes to mind, but what else?

The Witcher series maybe? I haven't actually played Ultima 9.

Risen as well.

I go with Garran. Elder Scrolls are much closer to U9 compared to Witcher and Risen.
You can enhance the older ones like Morrowind tremendously using community mods (take only texture patches, if you like it vanilla in terms of content).

I would say Gothic is closest. Elder Scrolls is all stale politics with 1000 people that spout useless trivia. I don't actually hate it as much as it sounds, but if I were to pick the closest one, I'd say Gothic. More interpersonal relationships, less generic kingdom sim.

The recentish TES games seem to have the same problems that U9 did though, especially in terms of generally dysfunctional NPCs and world physics (unless Skyrim is better in that regard?) And I've never been too fond of how TES quests play out.

I am trying out Redguard, though, which seems neat, although dear lord is it an adventure to get it working.

I think Amalur is sort of closeish too, although it doesn't have the freedom of motion you get in Gothic/U9/Redguard, in terms of things like jumping/wall-grabbing/mountain climbing.

Skyrim is much better than Oblivion on both counts, and while Oblivion's dialogue system could produce a lot of braindead-sounding interactions, it and Skyrim both have actual dialogue-sounding dialogue rather than the "wiki NPCs" of Morrowind.

Skyrim also fixed some of the big complaints about Oblivion (out-of-control creature scaling and the clunky level/stat improvement system).

The eternal search to find a game as good as Gothic. I too liked U9 and all the others mentioned here (Skyrim, Risen, Morrowwind, Witcher - but Oblivion was meh).

I'm replaying U9 right now and it's still working for me.

Sadly, open world RPGs with great atmosphere that immerses you in the game world are few and far between. There are a ton of RPGs coming down the pike and the only one making Gothic type noise is Witcher 3. I like turn based combat but for me it can't beat the feeling I get for a Gothic (U9) type of game.

I picked up a Wii and have become rather addicted to Xenoblade. While there's not much in terms of world interactivity, the actual environments are pretty amazing, and all of the NPCs have schedules, and the named ones can have rather ornate relationship webs.

It's very much what I was looking for.

Fantastic game indeed. Try that one on next time people tell you the Wii has no good/mature games!

Oh, wait, Outcast's another super-obvious one I somehow missed.

... I really need to play that again. I was bad at it when I was younger.