Hello everyone, i like mining aspect of AG a lot and would love to see more miners around. About mining missions; unlike gas giant ones, solid planet missions are usually not worth the effort with current state since they are harder to find comparing gas giants, when planet is found, you get very few slots(4 to 9 most of the time) usually filled with science labs or miners belong to other players, which eventually causes issues between players or you just simply give up on that deposit1.
My suggestion is, mining missions could address a special asteroid spawn in dead space instead of spawning on a random planet or moon. That asteroid could spawn when you move to a specific location mission journal suggests( not when you accept mission otherwise dead space would be crowded with such asteroids). That asteroid would have decent slots only available for mining modules like regular asteroid belt slots and when mission deposit is depleted asteroid would be destroyed as well. I would suggest these changes for only mineral missions since gas giant missions are already easier to access and have lots of free slots.
1I have found that most people are friendly enough when you deliver a deposit to a player already at the planet.
The proper procedure is respectful diplomacy.
Offer to share the spoils (especially if there are mines present).
I have had a lot of luck this way. And if the response is negative, I simply thank the player, wish him(her) good luck, and move on to the next.
(edit because - if I didn't, you might not believe it's me)