Tom, moving the bunker further along the hole would have no effect on the bogey obstacle rating since he gets the point (doesn't lose one actually) if there is a fairway bunker anywhere on the hole while they have to be within 20 yards of the scratch golfer's landing area to count for him. Of course, this would increase the scratch rating slightly so the slope could go down if the bogey rating didn't change. Unless this was happening on a number of holes, the change would be so minimal as to probably not matter.
Since the rating is about 85-95% based on length, the changes to the ratings base on restoration would probably be minimal. For example, if you widened all the 14 fairways (assume 4 par 3s) from 25-29 yards to 40-50 yards wide, you would subtract 14 fairway points. This would come out to -.17 obstacle value points on the scratch golfers and .35 points on the bogey obstacle rating. In other words, the course rating would go down by ~.2 and the bogey rating by .4 based on a fairly significant change. Additionally, the Rough and Recoverability rating would also go down because the fairways would now be over 40 yards wide. But, since the new middle of the fairway might bring new green side bunkers on the line of play, carry factors might occur that didn't before.
I would ask the players who complained about the possible effect of this change how often they are shooting par right now and if they weren't why they thought it would be bad if the course played slightly easier if it was more interesting because of it.
As for Dennis' question, while the scratch golfer can carry it 225, I believe that any rater I know would call this a forced layup. I would have the scratch golfer layup to 215 adding 35 yards to his effective playing length. The Bogey golfer would get a new water rating (assuming no other water on the hole) of 2 and the scratch golfer 1. The 35 yards of added length would increase the scratch yardage rating by ~.15 strokes while the bogey golfers would not be changed. The Scratch golfer's fairway number would be decreased by 1 because of the layup, but his green target would probably go up 1 or even 2. So, in general, the scratch rating would go up ~.2 while the bogey rating would probably be unchanged. This means the slope would go down.