Its an interesting topic. By chance when i started playing, the mission board was so not lucrative and undeveloped that you were better off going to the sandbox to get started. All the guides on youtube and reddit suggested going bounty hunting as the first thing you did. Watching this change and evolve over the years was a little bit dismaying. It was obviously a response to new players (??) seeing the inadequate mission board first infront of them, not having seen any guides, and making complaints loud enough to move the mountain to get frontier to act on it. Then there was the snowballing effect of the people who were accommodated by this making further developed complaints and frontier continuing to respond, for years the sandbox was long forgotten and languished while frontier changed the systems and watched the effect on steam reviews. The sandbox pillars for years became role play (i was fine with this).
I thought the best time of the mission board was around 2.1 to 2.2. Frontier every patch was connecting the mission board closer to the bgs.. and there were really lucrative outlier conditions as well where if you combined bubble location, population, station economy, controlling faction government and economic state, you could go and FIND within the bubble stations that had nothing but lists of stackable missions of exactly the type you wanted to play. The exploration and goldmine game was so good. I did for hundreds of hours finding my own systems which you could stack skimmers, medium range cargo delivery, data delivery and get superpower rep that wasn't one of the publicly known ones. I loved it. You ended up with a handful of systems which you could look in and if they were boom say know it was up for exploiting. That's how i earned my credit balance anyway. Of course this was too hard for the majority to work out. Every upvoted complaint i heard about stations with no missions filled me with dread and we are were we are today... zero variation except based on station economy and possibly a really weak influence from active state.
The main intention i get from the mission board is a year old balance pass of what frontier want you to be earning off missions, same base stacking completely removed (and replaced by wing missions, not the same).. and zero value in trying to find another station apart from the one you're on.
For personal fun i going back to the sandbox might be it. Its probably a royal shame that anything interesting out of the stations has been watered out if anything. It was fun having a reason to go explore the bubble. Roleplay it is.