Personally, I liked the move and their rational for it did make sense - THe pit is for going fast, while the NMD were constantly being streamlined to make them faster, so why not move the fast activity to the Pit and pump NMD’s full of masterworking materials.
The fail rate, is to encourage gameplay. Get you back into running those pits and to create a bit of friction. System seems to be working pretty well so far. Had a few fails, had a few lucky upgrades, onwards and upwards.