Definitely a very interesting topic, and I'd like to make my first contribution with something that perhaps hasn't been mentioned much: the ammunition for EDENCOM ships.
The mechanics of the ammunition for EDENCOM ships involve acquiring certain items plus ISK, which are then exchanged at DED corporation stations for the respective copies. So far, everything is perfect. However, I believe the disparity in items required to manufacture T1 and T2 variants is entirely misplaced. Against all logic, it turns out to be more economical to produce the T2 variant since it doesn't require hard-to-find materials, while the T1 variant almost demands a ritual sacrifice, unicorn tears, and nuclear engineering. In my opinion, the components needed to craft these ammunitions should be adjusted according to their tier.
For my second point, I think it's necessary to review High Sec incursions.
The incursion system is very simple: NPCs deploy in a random area, a group of players forms, and they destroy the combat sites until the incursion can be defeated. However, this type of content has been controlled in High Sec for years by a limited number of groups who reserve the right to invite more or fewer players to complete the objective. This, combined with the significant resources that can be amassed with each new incursion, results in a very safe area of the game where you can amass a large amount of resources with minimal risk, in addition to this content being monopolized by these few "elite" groups.
Lastly, my final point, and something that has perhaps been discussed on several occasions, is the use of cloaking.
I understand that it can be especially fun to simply float in enemy space for many hours waiting for the right moment to strike, but this can become really frustrating when you're on the other side of the story. It’s a necessary gameplay mode, and some adjustments have been made to provide some way to counter this mechanic. However, I believe it could be fine-tuned even further, for example by requiring specialized ships for these operations to carry fuel to maintain their cloak for longer periods (I’m not sure how viable this is, but it’s my proposed improvement).
I know that some or perhaps none of my points may seem like real problems in the game, but the idea of these spaces is to debate what is considered overpowered and to learn from everyone's feedback.