I can actually understand both sides here. I've played on and off over the years and honestly, this has been the most fun that I've had versus many other iterations. Missions/bounties are definitely very strong, and absolutely the best way of making money at the moment, but I don't think they should be nerfed. This is coming from someone who was explicitly a trader and quasi-lawful smuggler for literally almost 8 years on and off.
Rather than nerf missions, this should actually prompt a deeper look into other money-making methods, for example why not just make trading more interesting? Missions are actually hard to get started into, but once you have the equipment and ship, then you can begin to make some serious money. This is exactly the same as trading, mining, salvaging (the latter in previous iterations). The larger you go, the more you make.
The supposed issue you are actually talking about is the top middle bracket of missions, where someone in a Battleship/Dread can just farm gunboats/cruisers for seemingly infinite amounts of money. Solo this is okay in my opinion because it takes a while to ramp up to that point. The problem is this then gets multiplied per person in a group of players. Create a train of players, all doing the same thing, you go from making 100+mill an hour casually to literally double, triple, quadruple collectively, based on the number of people in your group. If you pool your money together then bingo.
Before someone says, 'But you can do that with trading ships', you are right, but there always had to be significant investment beforehand, for example putting everyone into an advanced train, running the train, buying the goods, risk of getting pirated or losing it all, etc. This was a fun time because you would hire escorts, have loads of RP, people would group up to pirate you, and so on.
So, as I've said this current version is very fun, but going from making 100mill an hour to 300mill an hour by literally just having three people in your group who might not even contribute, completely negates the risk of the mission, but increases your collective rewards exponentially. Bare in mind, that the number I have pulled is also a conservative number, based on what I and a group as fresh spawns have been doing in gunboats/destroyers. I could only imagine how much more you could make with a group of BS/Dreads. I imagine if you pooled your money you could literally get a fresh spawn into a fully fitted battleship in an hour or two, something which used to take months.