I question how useful this would be (I like the idea in principle but...)
From a purely statistical standpoint the population sizes are too small and the ratings are too course to give any meaningful information in a single value (as are the averages in reality). Standard deviation refers to the variance from the mean in a normal symmetrical distribution (ie where mean, median and mode are equal) and ratings do not follow a normal distribution, they are always skewed or truncated, it is very (very) rare for an album to exhibit a normal distribution to the point of being essentially unheard of. For example ITCOTCK, CTTE, DSOTM, TAAB and SEBTP are all skewed or truncated distributions... and there is nothing wrong in this, it's what we would expect because people cannot give greater than 5 or less than 1 ratings to albums and they can only give whole-number ratings and because ratings are subjective and they are not actually comparative and our "population" is naturally biased and naturally polarised. So this means it is practically impossible for anyone to give a rating that is the mean, median and mode value. The standard deviation can be used to calculate the degree of skew in a distribution but you cannot do that from the mean and standard deviation alone, you need the median or the mode but even that is not enough to tell you that the ratings are polarised, or wrong, or buggered-up, or misleading.
The distribution graphs on each album page tell you a lot but they must be viewed with caution, they can reveal that opinion is polarised or divided but not why that is so, you cannot look at the graph and determine why the distribution is as it is. A standard deviation value tells you even less.