Standard Deviations are still according to me the best way to learn how consistent a player is because averages do not take into account the strength of the opposition, for all the cricket India play it could be that Sehwag played a number of tests against the likes of the Bangladesh, WI, Zimbawe, NZ that kept his average above 50 who knows?
He can take a game away from you
but strangely enough his performance has very little impact on the overall result...
Ok lest see how Sehwag does against big teams.
Vs Aussies: 48
Vs England: 27
Vs NZ: 44
Vs Pak: 91
Vs SA: 50
Vs SL: 72
Thats an amazing record. You can keep your deviation theories. If a player has over all average of 30 and keeps scoring 30 in all games will you call that as Consistency? Dude Standard deviations are not used to measure how consistent batsman is.
Sehwag is a opening batsman, so chances of him remaining Not out are very slim still he averages 52 after playing 92 tests. If you are not consistent you wont anywhere near that.
Like I said, Sehwag is not consistent in tests is like saying Messi can't hack on cold tuesday nights, everyone knows both are bs and clutching at straws.
I have proven his consistency by posting his averages in a calendar year, against big opponents. You can draw whatever conclusion you want to.