definitely a negative connotation

shady? shadowy? Have you found no references on assessing the clarity of wine?

"Used to describe a wine that has small amounts of visible matter. Characteristic of wines that are unfined and unfiltered", according to The Spectator Wine Glossary.

http://www.winespectator.com/glossary/index/word/H

depends on how you interpret voilé, trouble, because why is it so?

According to a master sommelier:

Brightness: is the potential of a wine to reflect light, itself a function of the wine's clarity. Tilt your glass of vino forward against a white background (don't spill it). Observe how much light is reflected in the glass and on the white surface below the glass. A little? More than a little? A veritable rose window of crystalline reflections? The brightness scale is as follows:

Cloudy - Hazy - Dull - Bright - Day Bright - Star Bright – Brilliant

http://www.timgaiser.com/how-to-taste-wine.html

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Note added at 2 hrs (2013-09-17 12:51:13 GMT)
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I do see that your list isn't going to match this one, term-for-term, but suggest 'dull' as an appropriate rendering of your term.

Next we’re interested in brightness: how does the light glisten on the surface of the wine? Is the wine radiant, lustrous, luminous, vivid, lively, bright or lacklustre, dull, flat? Brightness relates to acidity in the wine: a vital component. Wines lacking acidity will often taste dull and flat.
http://winegeek.co.uk/about/wine-tasting-for-beginners/

Brightness: Is the wine dull or is it brilliant? Brightness is related to acidity. Wines with relatively high acidity will be very bright, while those lacking in acidity will look more dull in the glass, and may consequently taste a bit dull.

Clarity: Is the wine clear or is it cloudy or hazy? Ideally, the wine should be clear. A clear wine indicates that it is a healthy wine. If the wine does have a muddy appearance, check to make sure that it is not just stirred up sediment before dismissing the wine as bad. Older wines may throw a sediment and, if not decanted properly, it may end up in the glass. Don’t worry, sediment is not harmful. As a result of the recent trend away from the harsh treatment of heavily filtering wine, some relatively young wines may also show some sediment. Again, these wines are perfectly healthy. If you suspect a wine may have sediment then decant it into another vessel, or just don’t pour the end of the bottle (leave about an inch at the bottom).
http://www.simply-sommelier.com/sight.html

Brilliance

The brilliance (or bright) indicate a certain "vibrancy" of the wine due to its level of acidity.

Vocabulary used to describe the brightness of a wine: crystal-clear, glossy, bright, dull, drab, and so on.

http://www.bourgogne-panorama.com/home/wine-tasting/look/

Each uses a slightly different list, but 'dull' is a common denominator.

http://www.cantineditalia.com/glossary1.htm
"Limpidity
Limpidity in a wine corresponds to absence of haziness, that is of suspended particles in the liquid. This term can also be applied when there is an acceptable level of impurities perceived at normal sight and light conditions by the taster during the visual analysis. According to the degree of limpidity, a wine can be defined: Veiled – Quite limpid – Limpid – Crystal clear – Brilliant.
Veiled
A wine with strong opalescence (opacity) due to suspended particles. It may be caused by different factors: malolactic fermentation, pathogenous refermentation, casses. There are, in general, abnormal conditions.
Quite limpid
A wine which shows a very slight haziness due to suspended micro-particles, usually caused by long ageing periods. In this cases you must handle the bottle with particular care while pouring the wine.
Limpid
A wine free from any suspended particles or sediment. You can verify the limpidity reading an inscription trough the glass of wine and checking if the outlines of the letters are perfectly sharp.
Crystal clear
A wine which, besides being totally free from suspended micro particles, has a particular intense brightness and sheen.
Brilliant
A crystal clear wine which reflects the light passing through it. The bright reflections are often intensified by the action of carbon dioxide, which has the property of refracting rays of light through the colouring substances of wine, a characteristic of sparkling wines."