is Sangakarra the first batsman to be considered great/greatest only in his final year or two of cricket?

[Gambit]

Well, is he?

[Ram]

He went from 'Good' to 'Great' status after this game - http://www.espncricinfo.com/ci/engine/match/291339.html So, the answer to this question would be a 'No'

[kosingh]

No. It's just that only in the last few years of his career was cricket without Tendulkars, Pontings, Laras, Kallis etc stealing the spotlight. But he's long been considered a great IMO.

[Vijy]

He went from 'Good' to 'Great' status after this game - http://www.espncricinfo.com/ci/engine/match/291339.html So, the answer to this question would be a 'No'

Indeed.