One thought I have had is for a 6,000 yard course (Maybe the exact length is shorter) with one set of tees. Par for those playing from the “tips” might be 66. Par for the 18 handicap might be 72 and par from the forward tees 78. Might make for a more social and quicker game. It would be interesting to see if such a course could present an interesting variety of challenges for all.
As for par on pro events, the only real purpose is to determine who is leading midway through the round. Average score rounded to the nearest integer might be an improvement but not much of one. A series of birdie opportunities or tough holes creates a unique set of pressures that adds to the drama.