Most (if not all) of us would take the most conservative solutuion available if faced with a MGB malfunction. I think we can agree on this. That's the operational aspect of this discussion.
But the thread stated with a technical question (not the operational issue). MGB technolgy has improved dramatically over the years, both in design and manufacture. To compare today's MGB certificated under JAR/FAR 29 to older designs is not really relevant except to demonstrate how all things improve with time.
I would prefer to fly a MGB which has actually been tested to a level
in excess of the minimum requirement rather than the other alternatives. And that demonstration (necessarily in a controlled environment) is still better than one only meeting the minimum requirement or not tested at all.
And, yes, an emergency source of oil lubrication to critical components being available after total loss of MGB pressure is better than running dry.
You make your operational decisions based on your equipment capabilities and weaknesses, along with your situational condition.
