Hi Jussi,
Thanks for sharing your experience and findings.
Speaking from my own experiences and this is just my opinion so shoot me or agree with me, but this is my 2 cents worth
I do not subscribe to the "high drag" way of fishing, instead I fish with a lighter drag setup and palm the spool to apply sufficient pressure as required. To date this has worked for me and I have suffered very few braid, leader or terminal tackle failures. A lighter drag setup would also be more forgiving for strikes closer to the boat. Obviously we all get reefed, and get cut off by the tail scutes from time to time, but that is part of the game.
If loosely packed line from a days fishing were the problem , I think a lot more anglers would experience this problem, so I am not entirely sure that is completely to blame, as long as your line is spooled under good tension, this should be more then sufficient. I can honestly say I have only experienced the problem of line bedding in on the spool twice and both times were due to my own laziness in spooling of the reel rather then because of excessive use ! Lesson learnt
Something to consider perhaps is how you prepare your spools when spooling them. Are you using any backing and what type of backing are you putting down on the spool ? Obviously then the braid needs to be put on under good tension which I am sure you do.
Another thing to consider if you don't do it already, is use a different method of striking the fish near the boat as to put less impact on the knots and line. As you know braided line has no stretch and therefore the percentage of your impact on knots and weak spots are greatly increased the closer the strike is to the boat. Instead of using a solid heavy setting strike as one does when the fish take further out, use shorter, less powerful quicker jab type strikes with the rod parallel to the water, rather then tip up.
Just a few idea's to think about
Super interesting thread and look forward to all the input to follow