Equal turns are tidy, but treating them as the default can confuse fairness with sameness. A pull is not a ceremonial duty; it is a choice about how the group spends its effort. If the strongest rider is doing the sheltering, asking each person to take an identical turn may be less useful than letting that rider volunteer for more. But making the strongest rider responsible by default is just the same rule in reverse.
For a headwind stretch, I’d favor agreeing on the aim first: keep the group moving together, or share the work as evenly as possible. When the group hits a headwind, do you let the strongest rider do more of the sheltering, or keep turns equal even if the cost is uneven?