I think this whole shin akuma thing is pretty self explainatory. It can easily be inferred that the shin akuma appearance (white hair and purple gi) is what he would most likely look like these days. It represents his current incarnation and if they ever go ahead with Street Fighter 4, Akuma would resemble the “shin akuma” character model.
For those of you, (everyone) who have played third strike you’d know that akuma was going grey by the 3 series (on the sides ala Mr Fantastic). Whether this is due to old age, as he was getting up there by 3 - possibly in his 50s or 60s, or due to an increase in “power” isn’t particularly important. Clearly by this stage he now most likely has white hair and has traded in his old gi for a shiny new purple one.
As for the alpha 2 shin akuma, who really cares - its like asking whether chun li wore her alpha costume or her traditional sf2 gear during the alpha series.
Putting the Rugal fusion aside and without getting into a major debate about cannon or anything like that, Akuma’s latest appearances as produced by capcom - snk v capcom 2 and capcom fighting jam, depict him as the “shin” character model.
Whether they call him akuma, shin akuma or charlie chan is of little to no importance. I’m sorry but some of the reponses on this thread have been borderline moronic.