Some people see Optimus as being boring. To me, he is stoic, jaded by years of war, and wizened by tens of millions of years of existance. Seriously, could you imagine fighting a war for that long? And have you ever seen someone who has experienced combat fatigue and shell shock? Combat fatigue drains emotion and leads to expressions of emotional detachment. You can't let yourself get close to anyone since you've seen so many comrades die. You are in a position of leadership so you must remain strong and stoic in the face of infinite adversity.
Another little note i thought of: the series has spent a great deal of time exploring the relationship of the kids and their Autobot counterparts. I may be in the minority, but I am very impressed with what they have done with Jack's character. Jack has earned the attention of Prime as a mentor and Arcee as a sister-figure, as well as seeing the other two kids look to him as a leader. I suspect that we will see teenage romance complicate things in season 2...
And I want to hit repeatedly Miko with a hammer or large blunt object.

I have enjoyed the first two eps of the Orion Pax arc quite a bit. I believe we are seeing that developlment of Pax to Prime, and the motivation behind it (as much as we can see in 22 minutes per episode, anyways).
And the Star Wars homage in Part 2 made me laugh out loud.
"We all fine here...umm..how are you?"
