In reply to Helonia VS Helvetica - Curious dearth of information:
Just to add something else to the conversation, and speaking about aesthetics in general, I am not sure it is possible to defend an argument that Helvetica is improperly spaced, and I have to borrow another musical object to make the point.
Violins are bilaterally symmetrical, however, many of the greatest violins by the Cremonese masters (stradivari, Del Gesu, Bergonzi, etc.) have subtle bilateral asymmetries, and there are those who would say that these idiosyncracies, which could just as well be called flaws, are part of the attraction.
It seems to me that there are an infinite number of possible spacings for a font, and each will lend a slightly different flavor to the text. Whose to say which one is definitive. I would love to see samples of the same text kerned in various ways, to learn something about this variable.
Up until three days ago, I had no idea fonts could be so interesting.