hmm, i think she's supposed to disagree with that statement. by studying the process of transformation, the plot/characters are essentially the same but it allows us to compare the context and values etc.
for example, the hierarchy-
in Emma, class structure is based of blood, land, wealth.
and with the study of transformation to clueless, we see how this hierarchy has been translated to popularity based on appearances and wealth.
and she'll have to back this up with Austen's use of authorial intrusion, how everyone acts in the hierarchy (esp. mr knightley and his noblesse oblige). and also talk about the film techniques used in clueless (opening montage > reflects the values in the modern context)
and using these techniques, she should talk about how Austen's use of authorial intrusion, wit, satire etc gives a social commentary. i personally think that she is quite content with the strict class structure although she might be a bit critical of the place in society of women like miss taylor and particularly jane. Heckerling, on the other hand, uses satire to criticise the modern values, like Cher going shopping to sort out her problems.