So the end result is building a PC (even with a modicum of optimization, not the crazy OP levels that have PCs hitting on a 2 or 3 for every attack they make (and also sliding the enemy 5 and knocking them prone), etc) that tries to meet the 65% ratio as the game encourages, and then that PC basically autopasses Moderate DCs with the same skill, which is no fun either! It's this paradox that is my criticism: if one wishes to maintain the same math that the game encourages and explicitly spells out, the bulk of the challenge in SCs (ie, the Moderate DCs using primary-stat, trained skills) are no longer challenging.
I usually used Stalker0s version which encourages everyone to participate. You can search for it here on ENworld. It’s a X successes in 3 rounds of rolls model (rolls = # of char in party x 3) and the math seemed to work pretty well.