Couldnt agree more.
I think whats been amazingly done by the Telltale team is you felt exactly what Guybrush was feeling. At the start you didn't buy the 'goodie goodie' act and felt convinced at every turn he was going to stab you in the back. When you had to grab the turtle I was 99% sure he was going to push Guybrush of the cliff and so on. Then as he seemed to prove himself and Guybrush started to trust him more that was when the player also started to trust him more and when he came to help Elaine and Guybrush at the end of ch4 you actually felt pleased to see him which made his revalation even more shocking.
I remember as a child (and even now) playing MI2 being terrified everytime Lechuck appeared in the corridor as Guybrush and feeling the real urgency to get the doll made fast - which is part of what made me fall in love with the game but in EMI LeChuck was just being used as a meek puppet and all that dramatic tense feelings had gone.
Definatley back to his best.