I think some things need to change on a player level and not expect the devs to fix everything for us. I would suggest these things if I running a blockading a goal. Now I know this will get ripped apart because that's what people seem to do on this forum so whatever. I realize that most people will dismiss it but hopefully some people will think its a good idea.
One thing we know for a fact is there is nothing a blockade can do to stop a goal from being accomplished. There are too many ways around that. Okay fine.
When an area gets overan by pirates/blockaders a few things happen
1. After loosing a few ships/ cargo to blockaders the traders say screw this and go to solo/private (for the most part. there is always an exception)
2. Someone ALWAYS dumps thousands of tons of cargo in front of the said station. Haha real funny but it got old about 4 CG's ago. All that does is send people to private or solo because the system cannot physically handle it.
3. With all the traders going to private or solo you end up with an instance of 20 pirates all just sitting around looking at each other. If a trader does manage to land in the instance its like fly's on poop and everyone goes running. It's kind of funny sitting back and watching 20 CMDR's try to be the first one to interdict a T6. Funny sad.
4. You end up with private open play instances. I have experienced this twice. No matter what I did I could not instance with the pirates, so I essentially play worry free in Open.
So far every thing peopl do to blockade CG's is counter intuitive. Every action the blockaders do send people to Solo/Private or they create these new private instances.
As I said earlier the CG is going to get done. Nothing you can do about that. So why not reward traders by staying in open? Don't kill them, no matter how much they run. Just shoot out their drives. Even their cargo hatch if you like. Let them reboot and make another run at the station. Rinse and repeat as neccessary. With the trader knowing he is not going to be blown to smithereens every time he appears in SC he is more likely to stay just for the challenge of breaking the blockade. It will also give more traders in SC for the blockaders to interdict so they are not all chasing the one that appears at a time.
Stop dumping thousands of tons of cargo. Like i said this is childish and is working against what you are trying to do. I was with a trading group TS and all I kept hearing was. Screw all this cargo laying outside the station. Going to solo/private. Once again counter intuitive for the blockaders. Besides. It's a shadow ban-able offense. (Maybe next CG I will just sit outside a station and get someone doing this on video to submit to the devs.)
So to all the leaders of the major groups I challenge you to challenge the way you and your players play. I bet you would find more players in open if you made these changes, which increases the value of game play of everyone. If your on the blockading side I challenge you to not do things counter-intuitive to the game immersion you are trying to produce. To all groups trading, if the blockaders are doing what I suggest and not shooting themselves in the foot, I challenge you to stay in open. More traders = more fun for everyone. I know I would certainly hop in my trade Conda and make some runs if I knew people would play in this style. Other than that I just stay away from CG's in trade ships. It's not worth the frustration. I play to have fun.