Ozymandias is first and foremost a metaphor for the ephemeral nature of political power, and in that sense the poem is Shelley's most outstanding political sonnet, trading the specific rage of a poem like “England in 1819” for the crushing impersonal metaphor of the statue.
A want is something that someone had the desire for, but doesn't necessarily need. A need however is something that the person may not have a desire for, but is very important.
New England is the closest to standard English