I think everyone is upset with the rule because they’re not getting their way more so than it’s not working for its intended purpose. It’s a political point of contention more than people looking at it objectively and realizing everyone is getting something out of it.
I also think it’s probably the most fair rule, though I’m not against your idea either where the highest caliber players can still make their way into the NBA without skipping a beat. I just feel that too many will think they’re legitimately ready and teams will fall back into that old system of chasing potential before they can really analyze it. They definitely chase it today but trying to determine a player’s NBA value against high school level talent is an impossibility. Even one year in college proves wonders in that regard, I think.
But the loopholes in baseball have made it trickier — I’m sure you’re aware, and I feel that the NBA / NCAA would have to modify those so that college basketball isn’t watered down by great players choosing to play at Wabash Valley or Walters State or whatever.