I personally think it would be great if pilots could choose from a list (or database) of available flight plans based on real routes, created by other pilots, instead of having to create it from scratch before every flight.
This touches on the topic of this request which focuses on saving your own flight plan.
Being able to select existing flight plans would make it all even more real.
Maybe a team could be formed to create those flight plans.
This is already on LiveFlightConnect. You type in either the flight plan code or a route and you get flight plans to choose from. Pretty handy if you accidentally delete it.