I don't think par 5's should be 3 shot holes, period the end. We need to bring par back to 72 or make'm all par 4's for the pros.
I am not sure I understand what you mean. Aren't par 5's designed to cause the player to hit 3 shots in order to reach the putting surface? Anything less becomes a par 4. So how exactly can a par 5 not be a three shot hole without changing the definition of 'par?'
I think the best par 5's fall into one of two categories.
Great par 5's can be either reachable, risk/reward holes, or virtually unreachable three-shot holes.
If risk/reward, there must be both great risk and great reward. None of this getting away with a sloppy shot, but also a way around for the higher handicap and a complicated lay up for those not willing to take the risk.
If virtually unreachable, the usual challenge to the GCA is making the second shot interesting. Nothing does this so well as a Hell's Half Acre hole, or a hole like #14 at The Old Course with a bunker like Hell Bunker that dictates strategy the entire playing of the hole.
One reason I loved Elie is Scotland was that there were no mediocre par 5's! In fact, no par 5's at all. I didn't know what to think about that, but loved it!