I haven't touched video games in years, but I did spend time playing Delta Force in the 90s. Voxels were a perfect fit for the 300+ meter military engagements DF1 was attempting to model. I tried one of the latter entries in the series after they "upgraded" to a standard 3D engine and the sense of space was lost.
I can recall when Ultima 9 was originally conceived it was anticipated to be isometric 3D RPG. Here is a screenshot http://i.imgur.com/MGDSXYP.jp . Voxels would seem to be a great fit for such an engine.
I remember as a teenager I had the first issue of PC Gamer that talked about Ultima 9 and Ultima Online - I must have read it 1000 times. It was a shame U9 never lived up to its plans (I blame EA! :), hopefully Garriott has better luck with his current venture.
The exult project (http://exult.sourceforge.net/) has done much of the hard work in terms of making game data available. It would be neat to see a voxel engine transplanted into the old game.
I can recall when Ultima 9 was originally conceived it was anticipated to be isometric 3D RPG. Here is a screenshot http://i.imgur.com/MGDSXYP.jp . Voxels would seem to be a great fit for such an engine.