Just done this calculation for my handicap, I would drop a shot, based on the best 8 from the last 20. I also did this calculation for a couple other players I know, and it worked out they would either be +1 or -1. Therefore I suspect that handicaps wont change significantly.
Postive:
1. In terms of intention, I think it's goood that your handicap is based on your 8 best scores out of 20, and therefore your handicap is a true reflection of your best potential playing ability. I personally hate seeing my handicap going up 0.1 when I know I've played better than the score (I know this is an oxmoron).
2. Potentially a good initiative to combat against bandits, there are players who like to get their handicaps up for certain times of the year before competitions, to gain that extra 1 or 2 shots. Currently they can do this by deliberately playing 3-4, or 6-8 inflated rounds to achieve this. In the new system, I suspect they would need to play significantly more inflated games to achieve this. So on this front I think this could be a good thing.
Negatives:
1. Some players may not play 20 rounds in a year, and in fact a lot of fair weather golfers rarely play more than 10 rounds per year, therefore your playing average could be across 1-3 years in some instances. I would be interested to see what type of handicap this produces. My guess is that there may be a time limit on the scores that can be used.
2. It's a pain to calculate and many wesbites that manage handicaps will need to introduce some new formula into their databases to calculate new handicaps.
3. Finally some players may achieve a lower handicap than their true playing abiltiy. I know many players who dont submit their scores when they have a bad game, therefore for them they will potentially be submitting their best 8 scores from the last 30-40 rounds...
I think overall the postives may outweight the benefits, so I will wait and see if it does, does not come into force. My hope is that it should help players to lower their handicaps more easily if they are improving marginally over the year, I dont think the current system does this well.