Final answer:
Dr. Rearick's lecture does not explicitly mention Cassio's other weakness besides his inability to handle alcohol, but in the play 'Othello,' Cassio's inexperience and naivety are exploited by Iago.
Step-by-step explanation:
The weakness of Cassio in Shakespeare's Othello emphasized by Dr. Rearick, besides his inability to handle alcohol, is not explicitly stated in the provided reference texts.
However, based on the play, another notable weakness of Cassio that Iago exploits is his lack of experience and his naivety, particularly in matters of politics and manipulation within the military hierarchy. Iago uses Cassio's trust and his own reputation as an honest man to manipulate others and engineer Cassio's downfall.