there is some flaw in your teacher's argument
'it doesn't fit all the conventions of revenge tragedy'
but the point is that there really isn't a list of conventions that that ALL revenge plays must adhere to. and i'd be shocked if you jsut chose texts because they all had corresponding themes and conventions. the point is to recognise that not all revenge tragedies are the same and to struggle and grapple with different notions of revenge, also acknowledging some similar conventions and some different ones, atleast that's what i think a sophisticated response would have.
hamlet is a great revenge tragedy for many reasons, unlike other plays shakespeare is one who has developed this whole other aspect of revenge tragedy, what happens when revenge is forced upon you, you don't want to , but you are forced, how does a character deal with that. its one of the most psychologically haunting plays. the tragedy at the end is not that he died but the pains he went thru trying to grapple with his task. shakespeare protrays revenge not just an act, he dpoes more, he explores the mind, the psyche of the revenger and an unwilling one. how revenge poisened his psyche et cetera et cetera (i know i am crapping on) there are shight loads of good quotes, intertextual allusions.
i did revenge tragedy last yr and i was inthe same school as the chick who topped 3U english in the state. our teachers all taught us Hamlet as an extra text and made us go find other ones.
but i guess you'll have to read hamlet and judge for yourself whether you thinkits worthy of usage as an extra text
. personally i don't know how you could do revenge tragedy and NOT mention hamlet.