Cortana should be able to say the time, like "Cortana what's the time" and also she should be able to lock the phone like saying "Cortana bye" or "lock screen"
It woukd make sense if cortana had a handsfree functionality, which is probably not available because she's still in beta so we'll just have to wait. Untii then, uservoice is your voice. There's probably somene sharing your thoughts there. Just go and vote =)
1. The time is great.
2. What's the reason to add the option to lock the phone through Cortana, if you have the autolock and your phone does nothing unless you press with your fingers..?