I find that repairing damage in combat zones becomes increasingly impractical due to the massive percentage rate hikes, and I believe that this would be a good solution to mitigate traveling back and forth from an industrial hub after every mission in Tier 14-15 regions, as well as making purchasing insurance more justifiable.

For example, if you purchased a pip of insurance for 400k c-bills and had it pay out in full, but the regional combat zone had a bonus 200% tax on in-system repairs, the insurance would adjust to a total of 1,200k c-bills. It doesn't make sense to me that a region of space would provide 'insurance' that wouldn't cover the regional cost of repairs.