I do a lot of testing on length of shaft and play a 48 inch driver myself. From the testing, for each extra inch in length 1 mph club head speed is gained. Going from 45 to 48, a player might see 3 mph gained which can equate to 7-7.5 yards. The length of shaft can also give more height, which can mean a lower loft can be used and a few more yards can be gained this way too.
With the longer shaft, the swingweight of the club of the club will be heavier putting the balance out. Normally weight is taken out of the head to counteract this, which leads to a little more club head speed but a little less ball speed conversion due to less mass in the momentum equation. Lighter heads are also a little less forgiving.
As most would know longer shafts are also less accurate for most but some do gain accuracy with a longer shaft. About 50% of golfers I see work best with 45 inches, about 13% work best with 46.5 inches and I can think of around 4 that are using 48 inches. In the greater scheme introducing a local rule of 46 will effect a small few but not many golfers, so I'll doubt you'll hear much chatter from anyone about this rule will destroy their golf career and enjoyment.
I find I don't really buy some of the rollback arguments, certainly don't buy the one about that's not the way the hole was meant to be played. I play with golfers who hit it 50 yards past me and also golfers who are 50 yards shorter than me, we all play the hole in a different way and that hasn't changed from 10, 20 or 30 years ago and won't change in the future either.
I don't buy the score comparison to the past either, the score really is only a valid comparison to other golfers over a given day or a given tournament, there is no real need to say that a 66 now is better than a 68 in 1965 given all the other factors such as course or weather conditions on daily scoring.
I don't buy the reports that come out every year that say that this is the year that equipment has finally gone too far, the big equipment jumps were between 1990 and 2004, since then gains in distance have been just a creep forward.
I also don't buy the players that say it's the improvement in players that's making the difference, that the players today are fitter and stronger and better coached. The best players of all eras were fit and strong and coached well and hit the ball far compared to the average of the time. Athletes like to think that it's them who are the reason why records are improving and not the equipment they use to help them, just look at the reaction to some runners to the new technology.
I am in support of a rollback because the longer the ball goes, the push will be for longer courses and as we know, more land, more resources, wider corridors, longer to play etc. A slightly more compact game by 10, 15 or 20% will not be detrimental at all and using less resources and time will only be beneficial.
A rollback and a shrinking will be a lot easier than many think and I'll give two reasons why, one it's been done already with the move from 1.62 to 1.68 and an anecdote for the second reason.
Back in the mid 90's me and two other young guys used to play with an elderly doctor on occasion in a fourball. He was a golf nut, would hit balls every day, read every book on golf, buy all the latest equipment and was very knowledgeable and insightful on the game. One day while he was out playing with us and we used to hit it 50-70 yards past him, he said I love playing with you guys, I just ignore how you play and play my own game but if I'm playing with my normal bunch on a Monday and one of them hits it 10 yards past me I'll jump all over the next tee shot to get past them and many times I hit a terrible shot.
The morale of the story is that, golfers don't experience playing with a big number of other golfers, they play mainly in a small enough circle and that's who they use to compare themselves to. It's not the total distance that matters but the comparative distance, if they all lose distance, they won't be concerned and that's why after a small bit of grumbling with a rollback at the start it will be ignored quickly enough and golfers will just get on with playing the game