The Champagne region is warming up, grapes are being harvested with high levels of phenolic ripeness. In fact in some areas the alcohols levels in the fermented juice is too high, making champagne with these vin clairs is not possible.
The below table over simplifies the matter. In the past champagnes were drung sweet, tastes changed. Champagne very slowly is being recognised as a good food partner, here it has to be dry to work with french cuisine, thus the rise of extra brut champagnes.
It is also important to understand, the harvested grapes have to undergo two pressings. The first called the cuvée obviously produces the best juice. The second pressing, the taille, does not possess the same quality. Some producers use the taille like Guiborat in their Tethys, others prefer to sell the Taille to the big houses and use only the cuvée. When the taille is used due to the quality of the juice a higher dosage is required to mask the imperfections.
Brut Nature = no added sugar and under 3 grams/litre of residual sugars
Extra-Brut = between 0 and 6 g/litre of residual sugars
Brut = less than 12 g/litre of residual sugars
Extra sec (or Extra Dry) = between 12 & 17 g/litre of residual sugars
Sec (or Dry) = between 17 & 32 g/litre of residual sugars
Demi-Sec = between 32 & 50 g/litre of residual sugars
Doux = more than 50 g/litre of residual sugars
In the past the Champagne region struggled to get the grapes ripe. One vintage in ten was perhaps a great vintage. Now every fourth vintage is hailed as a great vintage. Grapes are being harvested earlier and with higher sugar levels than ever before. When ripeness was a problem, dosage made sense. Now if the grapes are harvested with 11-12° and the resulting champagne is Extra Brut, this does not mean the champagne will have a tonic like dryness and possess high aciditiy. The champagne could actually be quite round and fruity depending on the grapes, vintage, site etc.
For these reasons I would be very reluctant to recommend a champagne on the basis of dosage alone. As producer champagne takes on the burgundian terroir values. Site, vintage and phenolic ripeness become the deciding factors on really understanding a champagnes feel.