There are some excellent insights in this. It captures Cassio's idealism (a
complete contrast to the cynicism of someone like Iago) and his romantic
temperament, which sympathises with the Othello-Desdemona affair quite
passionately (witness his speech at 2.1.75-83, where he looks forward to
the couple's arrival and the effect their presence and even love-making
will have on everyone's "spirits"). When Verdi made an opera of *Othello*
in the 19th century he started the whole story at this point with the storm
and the group waiting for Othello on the Cyprus battlements.
I'm not sure Cassio would refer to Othello's "sooty bosom" -- this is of
course Brabantio's supercilious and racist phrase. You use the Duke's
summing up of the race question very aptly (interesting that it still
assumes that white is good and black bad -- the Duke seems to be saying
that Othello is so virtuous that one could almost imagine that he's white).
There's lots of irony in Cassio's summing up as you imagine it -- before
very long he's going to be rather uncomfortable with Othello's "guidance",
and Othello is going to be anything but th e"self-controlled warrior" on
Cyprus!
