Right on. It makes no sense to have instigator rules and "last five minute" rules, if you're going to overrule them 75% of the time (or more) anyway. The NHL has had to violate their own written rules at least three times now, to avoid suspending players from opposing teams who started fights AFTER the game (or within the last 20 seconds). Either enforce the rule, or scrap it.
I think one solution would be to allow penalties to carry over in playoff series. It's the same teams in the same series. That would put an end to teams amassing 40 minutes of penalty time (including game misconducts) at 20:00 of the 3rd period, and nobody having to serve one second for the infractions.
We lost a key player for almost an entire game on a very questionable game misconduct call, but Anaheim, Chicago, and now Pittsburgh have amassed over an hour of penalty minutes, on undisputable infractions, and the most that was served was 18 seconds.