Both sentences seem very passive to me. I think I'd prefer a very apparent, active subject (we, because being surprised is the important word here, right?). Also, as David said, simplest is best.
I don't think Except is wrong in stating that "We were surprised that he was chosen" is more active. "Surprised" is a state of being--more like a noun than a verb--not an action. "Were" is the verb in that suggested sentence, and surprised here is an adjective (modifying we).
“His being chosen” vs. “His having been chosen”
Both sentences seem very passive to me. I think I'd prefer a very apparent, active subject (we, because being surprised is the important word here, right?). Also, as David said, simplest is best.
I don't think Except is wrong in stating that "We were surprised that he was chosen" is more active. "Surprised" is a state of being--more like a noun than a verb--not an action. "Were" is the verb in that suggested sentence, and surprised here is an adjective (modifying we).
Please, correct me if I'm wrong!