My problems with Barkhorn's design are:
* Annual Failure Rate is through the roof - do you use maintenance OFF?
* only one engine, you lose it, you are a sitting duck
* if those two classes are meant to be used mostly together why not to use those 1000t more on Donitz, bringing it to the same size and speed?
* range is also widely different, especially if Blutcher is sometimes meant to sit on one spot while Donitzes rushes forward
* unless you are low on fuel it may be worth to use stronger engines for faster ships, 14 % seems maybe too fuel-conservant - note Tree's ships are faster with 2 techs lower Ion drives
My problems with Barkhorn's design are:
* quite low maintenance life and high AFR
* MSP is less than double Max repair - if something big breaks you can't repair it yourself even if some other ship donates you supplies
* Kaifeng even has MSP less than Max repair - it can't itself even maintain its prices component
My designs are at
Ships thread next door. Feel free to raise your objections against my style of having reserves of all systems.