IMHO I think the game would be much more fun if you could place a Mine Control tower, define the area, then simply pick a resource to mine. Whatever trucks you assign will automatically dig out all of that resource in the defined area.
Get rid of manually designating mining areas
I think this is unlikely to happen. Mining is a key element of the game and has a lot of subtleties which are hard to automate. That said, more feedback on what a good move looks like and how to avoid running into problems would be a nice improvement.
While I do bitterly joke to myself that this game could sometimes be renamed "Quarry Access Road Simulator", I agree that the pain is integral to the experience of the game, and I would miss it. Perhaps some kind of late game tech to accomplish this would keep the early game challenge while easing the late game grind.
Too complicated to implement. Intuition predicts high chance of unsolvable mining situations with 100% possibility of happening. So, definitely nope.
Agree with the above comments about this being a nope. This game has loose material. So if you designate a harvester to go and mine all the coal, it'd never finish in some cases because the dirt would slide right over the coal and you'd be hard set, without building retaining walls (researched in mid-game) just to manage the resource area.