So I spent several years at the MGA president at a golf-only club with a LOT of really good players. The club ran a $20 points/skins game 6 days a week and input the scores into GHIN, and also had a lot of club tournaments with net competitions. I've also spent a lot of time and money playing local senior tournaments with both gross and net winners. And you know what?
1. The handicap system works beautifully IF it is properly implemented and monitored. ALL of the problems that are attributed to the system are actually human frailty and nothing more.
2. The single most reliable aspect of the handicap system is that better players don't like losing to lesser players, and are very often going to allege sandbagging as the reason. In most cases, the correct response to these complaints by low indexes is, "Then don't play in net competitions!"
3. #2 above is true in part because the purpose of the system is to allow for competition between better and lesser players, which makes golf unique, but is really exacerbated by the fact that "vanity" handicaps are far more prevalent than actual sandbagging. I believe the USGA estimates that the ratio is at least 3:1; I'd put it far, far higher than that. The percentage of golfers who give themselves mulligans, preferred lies, gimmes, and don't take full stroke and distance penalties and then submit the score is huge; when those golfers are then forced to play by the Rules, they can't do it, and if they play against a player with an accurate handicap, they lose and then bitch endlessly about sandbagging.
4. The bigger the field, the more likely it becomes that a high index will do well; this is simple math. The entire system works best for match play, and it works pretty well for flighted stroke play. But higher indexes have a greater range of scores than low indexes, and as the size of the field increases, so does the likelihood that a higher index will catch lightning in a bottle and win. That's just golf, and again, the answer to the low index that complains is, "Then don't play in net competitions!"
5. If a club correctly monitors the system, true sandbagging becomes really rare. It happens, but it's rare. If the club does NOT monitor and deal with problems, then that's another human problem, rather than a system problem.
6. None of this has anything to do with whether or not the new system will be better than the old. I think it WILL be better, both because of the net double rule and the weather adjustment IF those are done properly. Which brings us back to the human element, rather than the system.