Your point about leading questions being allowed for hostile witnesses makes the point of this question even less clear to me now. (law.stackexchange.com)
As @cpast correctly points out in his comment, the rules allow direct examination of hostile witnesses. (law.stackexchange.com)
Defence counsel must be both skilled at getting helpful evidence from friendly witnesses tendered by the Crown, and vigorously cross-examining hostile witnesses. (mcgarrylaw.ca)