Simply put, since I'm a much bigger fan of college hoops than the NBA, I'd like to see it change to 2 years before a player can be eligible.
Now I understand that everyone has the right to make a living whenever they want, but only a handful are job prepared out of HS and slightly more after one year of college.
Here's what I propose: (likely not realistic!)
Make it a 2 year w/ exception rule - Not allowing the highschoolers from jumping to the league right away eliminates the situation where a program loses one or more recruits who jump right to the NBA. It also protects the recruits that have been poorly advised and don't get drafted and find themselves having little to no basketball developmental options.
As for the exception part of the rule: Have the NBA and NCAAs have some invitation only evaluation event or events (weekend(s) or week long) where the best college underclassmen (includes Freshman, Sophomores & Juniors) are invited to be evaluated along with their body of work during the season. And from those participants, a certain number of them are selected to be eligible to enter the draft if they'd like, and advised on an estimated draft range. Note the criteria to be selected for draft eligibility would not be on "potential", but more on their projected capability of competing at the NBA level the upcoming season. For example, a LeBron James type talent would turn out to be a no-brainer, but a Charlie V would be exposed as not being ready and needing at least another year. Not meaning to pick on CV, but he's one that came to mind that could have used another year of college. At least that's what my recollection is of him, though I'm sure there are other players to use as an example.
This idea, IMO, protects almost all parties concerned:
Exception #1: Those rare highschoolers who are NBA ready like a LeBron James don't benefit from this idea. But how many are there each year and how often do they come around? IMO, not often.
Exception #2: The highschooler or college underclassman who turns out to be not as good as some had thought and shouldn't have been rewarded a big contract based on potential alone. On one hand, this type of player might miss out on money that he'll never get though really never deserved, but in some cases they might still would have been drafted at a later time once they were better prepared to play and even stick in the league longer.
NBA Franchises: It protects the collective NBA franchises from themselves where they won't be tempted to take a player predominantly on potential. There would be a lot less complete misses and a lot less players drafted higher than their abilities. Though with the latter, there will always be players who do not perform up to their drat position since you just don't always know how a player's capability will translate to the next level. I'd be remiss to not mention that if you allow high-potential players in the draft who aren't ready but might turn out to be great someday, a team that might have been willing to take the chance if that player was on the board at that time, end up missing out on that type of player. It's very likely when that type of player shows he's ready or has completed his sophomore season, might not be available when that franchise's pick comes along. Though I'm sure there are many franchises who wish they were protected from some of the lottery busts they've made in the past and wished they had a larger pool of both talented and NBA ready players to pick from that have much larger resumes than the ones they selected.
NBA Fringe Veterans: Every time one of these players who are not ready ends up on an NBA roster, there's a veteran who's actual capable of competing at that level loses his job.
College Programs:
1. Recruiting class protection - They won't miss out on a recruit that jumps right to the NBA and/or other prospective recruits they stopped recruiting because of a committed recruit didn't honer his LOI.
2. More stable and predictable rosters - Most programs will have a better idea on what players will likely to be invited and even selected for the underclass NBA draft eligibility process I described above. There is still some uncertainty but not nearly as much.
All college underclassmen: By having this evaluation process, it protects the ones that clearly aren't ready to be drafted or at least have major concerns, and if they get an agent, end up with little to no options to continue their development. Granted there is the D-League and overseas, but IMO that's not usually ideal for most 18, 19 or 20 year olds. It would also give the underclassmen who are likely draft ready more data to decide if they want to declare for the draft or return to college for another year to improve their draft position and earning potential. Granted there is no exact science to this, but it's better than the current process. Since there will be a lot more knowns about the players who are eligible for the draft and those draftees won't have to worry that they are also competing against a bunch of "potential" draftees, should give them a little better idea of their chances of being drafted. Adding to the mix a bunch who don't have much of a resume, would benefit most of the players who have put the work in and have demonstrated what they could do against the best at their level.
College Hoops Fans: I, along with many college basketball fans like to see the best young hoops talent develop their skills at the college level. I don't like seeing my program miss out on a recruit who jumps right to the NBA, or other recruits that my program missed out on because of that recruit committing but in the end leaving, like Andrew Bynum. I also don't like when a player leaves before I even get a chance to enjoy watching that player both contribute and improve. I would love if they would stay at least 3 years, but can live with 2. We all are enjoying watching Shabazz Napier the senior. We all would have loved to watch Caron the Junior. There would be an overall greater quality of college hoops if more of the best players are hitting March Madness with almost 2 years of development under their belts. (I wonder if a program like UK would benefit from this idea. We've witnessed that it takes a special mix of talented young players along with a handful of experienced returning players to cut down the nets. IMO, most years the Squids kids, as talented as they are, are just not developed or experienced to win it all. Though I do wonder how it would impact their recruiting. They are unlikely to get a big class of Blue-Chippers year after year. He'd have to either try to balance the number of 2-and-dones each year or live with having to reload every two years. Though if one or two of these types of players turns out to need a 3rd and/or 4th season, he might just have the right mix of talent and experience to be in the hunt for a NC most years. Kinda scares me a bit, but I think programs like UConn will get their share of talented players and having the mix of a couple of these 2-and-done type talent plus some very good 3 and 4 year players might be just as capable of winning it all. We've seen that type of UConn roster cut down the nets 3 times now.)
NBA Fans: As much as I'm sure most NBA fans would want as large a pool of potentially good players for their favorite teams to draft, I'm sure most would rather have NBA ready players on their roster compared to ones that just aren't ready to play and some that should never have been drafted or picked as high as they were. Draft mistakes will always happen no matter what process you come up with. There are players that the so called experts and us crazy hoops fans believe will be solid to all-star type talent that don't meet those projections and some that flew under the radar who turn out to be much better than expected. I think a plan like this could at least ensure a deeper and more quality draft most years with more ready-to-contribute and legit NBA level talent making up the draft instead of a whole slew of "potential" type draftees that might never live up to their capabilities and/or expectations.
Take Bazz for example. Now we don't know how good a player he'll be at the next level, but the player everyone is seeing this season is leaps-and-bounds more talented that I'd say most if not all of us thought he could be. Last spring, he would have likely been drafted in the 2nd round if at all. This upcoming draft, he'll likely be a lock for the first round and might even get drafted in the upper-half. Now granted Bazz showed his most dramatic improvement between his junior and senior season, but with this proposed idea could benefit a lot of players like Bazz who were able to improve dramatically between their freshman and sophomore, or sophomore and junior seasons. Although this idea might not sound all that American, though College FB and the NFL have this very same type of process, I think it's a win-win for most parties concerned.