Thomas Armstrong, in another post said 'I've always found that the limitations of 61.4 are too restrictive. I would like to read a discussion on how these restrictions were defined'. 

The bar for redress is high.  It always has been. The 'redress' that a boat can get when disadvantaged by another boat breaking a rule without physical damage or lack of sportsmanship is the penalisation of the other boat on valid protest.

Prior to the 1961 rewrite of the rules:

The 1961 rewrite provided:

Rule 12 Yacht Unduly Prejudiced
If the race committee decides that he finishing position of a yacht through no fault of her own, has been materially prejudiced by rendering assistance, or by being disabled by another yacht which should have kept clear, it may order te race to be resailed or make such other arrangement as it deems proper.

Rule 68 Protests
1.  A protest can be made by any yacht against another or against the race committee.
...
5.(b)  If the race committee decides that [an infringement of a racing rule or a sailing instruction by the race committee] occurred and that he result of the race was altered thereby, it shall cancel the race or order it to be resailed, or make such other arrangements as it deems proper ... .

In the 1964 version, the right to protest against the race committee was removed, and the wording of rule 68.5 was changed to refer to 'an action or omission of the race committee', and 'seek redress'.

In 1981 the provisions of old rule 12 Yacht Materially Prejudiced and old rule 68.5 were combined into an new rule 69 Requests for Redress, in more or less the form familiar to us.