I think it goes without saying, tidi is no fun to play in.
Currently, I think that the meta of as many people into system at a time is not fun.
My suggestion is a mechanic for damage, like the stacking penalty for remote repping.
How it fits in lore:
As a target is being attacked, debris and, explosions obscure the target. Reducing the amount of incoming damage.
Armor plates drift around deflecting laser beams, exploding torpedoes reduce the damage of other torpedoes.
This would also allow other mechanics.
For example, carriers. For some reason CCP hates carriers. They have no real purpose, they have no t2 variant, no faction variants. Dreads do.
Carriers could have reduced damage mitigation.
The lore for this would be fighters being piloted by crew (I think they are, they have the model of a crew?) they can apply damage to areas that are not effected by debris.
This would give carriers a multiplier effect on the field. And make them useful other than flying a dread. You have 50 dreads, lets say mitigation is at max at 10, why bring 50 when you can bring 10 plus carriers. It creates a niche that carriers desperately need. In addition to this, the mitigation would help in defanging carriers.
What would this mean for dreads? Well dreads are often fitted passive HP, because usually, you donāt last. The damage mitigation would mean active tanking in a dread can be viable. After a certain number of dreads shooting you, it becomes less and less incoming damage due to damage mitigation. (Damage mitigation could be more for dreads as everything is bigger, less for frigates since everything is smaller so the mitigation scales with ship size) So you could tank to cycle out of siege to be repped by the faxes. This would change the dynamic in null, would change how fleets work, would alter how coordination in large fleets work.
Ganking
How would damage mitigation help in ganking?
Well if you have 50 alts being run by someone multiboxing and they gank a freighter, the increased number of ships means little in that eventually more isnt more. It would make ganking more skillful instead of as many alts on target as possible.
In closing, I think something needs done with the Max people on field mentality. If 500 dreads on field means you have to have 50 people calling targets for groups of 10 dreads, I think we would see a shift in how fleets operate.
As a note, I live in null, so most of my comments are related to null. But mitigation would help in all aspects, even in ratting or missions.