Hi
When waking the display by raising your wrist (with that setting enabled), it stays awake for a few seconds. Without interacting with your watch, it is not possible to extend this time period.
The display can also be set to stay awake after interaction / tapping on it for up to either 15 or 70 seconds.
To set your preferred wake duration:
On your iPhone, in the Watch app, go to: My Watch (tab) > General > Wake Screen - under On Tap, select Wake for 15 or 70 Seconds.
If you would like to send feedback or suggestions to Apple, you can do so here:
https://www.apple.com/feedback/watch.html