Considering that the mission limit is 20, that's a nice exploit.

At least, I'm never allowed to take more than 20 missions, whether I have cabins free or not.
Wait seriously? I thought that only applied to skimmer and massacre missions or am I under the wrong impression? Either way 200mil/hr is the thread title I have which is where I got my numbers from
As for BGS - You are complaining it's hard to do things in your system because of tons of traffic. Yet you said the same profits can be made elsewhere. Then do something to move people along.
Advertise the other places with screenshots and make events or whatever, imagination is the key. Or make it dangerous to go to Smeaton by killing passenger carrying ships or posting messages into local chat in supercruise.
In terms of wars and affects from other players, this is the goal of the BGS, it's meant to throw you a curveball. You are not meant to play with the influences and always get your way perfectly as you want. Just because you have a player faction there doesn't mean you should dictate what happens and how. All players count equally.
However, all that being said yes it's a problem for you in that you were unlucky to be set up there at the current time given it's the "go to" place for cash.
But there's always going to be a "most profitable goldrush" system and the place for goldrush has changed every release from Quince to Robigo to Smeaton. You are currently in the unfortunate place of being "it".
Asking FDev to nerf it will only breed resentment and best case will pass the problem to someone else who will be "it". Personally I'd say do your best to damage control as above and deal with it as best as possible. Or wait for things to move on naturally as they will.
Saying it's killing the game and FDev need to act instantly to fix it etc as well as other incredulous statements are just going to make people laugh not sympathise.
First, you won't make person to play for longer if you slow their progress to a crawl.
Second, FDev could care less that people play for long. ED is not subscription-paid MMORPG, they don't receive regular revenue from active playerbase.
I have news for you, in fact, they only receive more server resource/maintenance expenses if more people stay for longer. From business standpoint its more beneficial for them if people don't remain playing game for long (they paid for this game/expansion already anyway).
I'd disagree strongly with this although damnit Cagman has ninja'd me. The best players for FDev are those that buy the game, buy cosmetics and do videos, screenshots and free advertising bringing other people to the game.
I'd guestimate 75%+ of FDevs profit from Elite is from the microtransactions that are cheap to produce, high profit margin and are not a once only purchase given the number of ships and options.
I'd argue people that play past 1000 hours probably spend more on cosmetics than they do on the game. I know that would be true for me if I hadn't got the lifetime pass, as it stands that tips the balance for me.