You chose: the end of the novel should be long
The novel has a notably short ending. Motooka recounts that for readers, "even if Arabella's concession to the patriarchy is not lamented per se, the abruptness of her alteration is: 'the ending should have been more artistically contrived,' writes one critic, while another speculates that the novel's sudden conclusion unhappily resulted from the pressures of Lennox's financial distress" (Motooka 251). Perhaps if Arabella's ending did not involve a conversion, the abrupt ending would not seem so drastic. Either way, the ending's length as-is feels disjointed, so it seems appropriate to extend it to match the pace and relative length of the rest of the novel. Every momentous scene earlier in the novel gets plenty of description and dialogue, so why not the ending, too? Maybe having enough time and space to really explore the characters' fates is what really decides whether an ending is good or not.