In 1968 there's the unprecedented possibility that a team based on the East Coast might be playing a team based on the West Coast (e.g., Boston vs Los Angeles) in the final. The usual 2-2-1-1-1 arrangement would (if the series went the limit) involve more long trips than would a 2-3-2 series.
However, because the new Western Division wasn't entirely "Western" the final could have been New York vs Philadelphia or Chicago vs St. Louis, which counters that argument somewhat.
If you have largely or entirely separate divisions (or leagues) , it isn't fair to compare won-lost records across the gap, and the 2-3-2 is expected to be fairer, hence the baseball logic. (In the 2-2-1-1-1 the first host gets any "odd" game.) However, the NHL increased the number of inrerdivisional matchups again and again, so this really didn't apply.
So, I'd say that 2-3-2 made sense early on, less so later. The league probably intended to alternate the series start annually, but that was swiftly overcome by events.