I am no longer with the TDR for quit some time now.
But no matter how I am thinking maybe the best is ask the people them self why they made the decision.......
No matter how I think one thing I did learned over the last couple of years : You can all wright about things and have your opinion but you can never reed the personal book of someone else unless you ask to read a chapter
I myself am part now of a Aatu tamaskan group that is also for outcross. I was against it for the temperament reason yes but they also have there arguments why they are pro. When talking without pointing and judging you can come to a point you do not have to agree but understand.
I do not know the arguments the TDR had but if they had the same as the TBA does I can understand it.....and that is why I say maybe start reading on the tamaskan forum or ask them