Well, from those two hours you have to subtract half an hour for emoji presentations and another half hour for uplifting 'one of every colour' videos.
😀 new Watch bands also, i'm looking forward to the Apple Watch announcement more so than the iPhone this year simply because it will look like my iPhone X from last year and from what's leaked already there probably wont be a point in upgrading this year. One more interesting thing we could hear is Airpower release date and maybe AirPods with "Hey Siri" announced.
Apple Watch - Series 4 - 30 minutes
iPhone - 3 versions - 45 minutes to an hour
Airpower and AirPods with "Hey Siri" announced - 10 minutes
I'm still hoping for at least iPad Pro's but we will see.