re: Standard practice is to design for the worst case scenario
Any time you try to lower the "Bar" you are chancing a failure. But if you want more missions then lower costs are needed.
I'm not saying Beagle 2's entry phase design was good. It had virtually no chance of success. But, I do believe the science package was worth the try and another Beagle type mission should go 07' just with a better aeroshell design and retro fire...