Only thing that OpenXcom could fix is to made smoke pseudo-transparent, but I dont know if it will look any good.
The PSX version is actually quite sophisticated effect in itself, not that it looks good in the game. Its a looped transparent smoke. The looping is perfect. The transparency however is ugly.
A better solution:I'm thinking about opaque smoke puffs and less transparent smoke parts than the PSX version. The soldier standing in smoke should be partially obscured in thick smoke patches per frame, but since the whole smoke is animated, different parts of the soldiers or aliens are visible at every frame.
Example
Frame 1..2: soldiers head is visible
Frame 3..4: soldiers torso is visible, head is covered by thick smoke
Frame 5..6: soldiers legs are visible, rest is covered by thick smoke.
The genius of UFO DEFENSE-s smoke - DOS version - is that it seems voxel-based and perfect for thickening and looping. While any conventional "sprite-based" smoke in the shape of an oblong rectangle doesn't look good on this grid system, since it does not tile horizontally and looks separated. The PSX smoke doesn't look good, it is ugly in its separated columns. Smoke should be a big thick mass, several tiles wide, for which the original smoke effect is perfect.
Any new smoke effect should be made tileable horizontally - isometrically - so we can see the genial thinking of Julian Gollops coder team here and implementation.
Lot of effects in the game just look simple to re-create, they are quite sophisticated in reality.