So, to get back to the OP, Crank weakness,
And how to make is stronger.
I think it can be assumed we are only talking about 1725 cast cranks.
Dave Anderson broke a 1725 cast crank, in his Vintage Race engine.
BUT, that crank was heavily stressed with high RPMs and power.
And, without giving up any National secrets, the crank Dave broke was no longer within factory STOCK dimensions...
So, How far down on the Alpine engine "Weak parts" list is the crank?
How many stock spec Alpine engines have had crank failure?
I would suggest few if any.
BUT, as you move up the performance ladder, the crank strength comes into play.
Also, in the performance window is displacement increases, via cranks with reduced dimensions (offset ground stroker cranks).
I can't see the point of taking a known weak part and making it weaker by stroking it.
I'm beginning to conclude the practical engine to build for performance is a 1592 with a steel crank.
Even though you start with a shorter stroke, the ability to stroke a 1592 is there.
And, at the end of it, you still have the steel crank!
At this point I get to over use the term "Win, Win".
DW