I think this is a very difficult question to answer in any consistent manner.

No course play the same for any 2 given golfers. That is the very essence of course rating. Different players at different levels have different skillsets, and the course has to be somewhat challenging for all.

That is why course rating are based on 2 elements: CR and SLOPE.

CR is an indication of the expected score by a scratch golfer under normal conditions, while slope is an indication of the relative difficulty of the course for a bogey golfer.

It is not at all impossible to make a course easier for the bogey golfer, while making it harder for the scratch golfer. The simple way is to move the fairway bunkers, so that they are out of reach for the average bogey golfer while being in play for the longer hitting scratch golfers.

Today, with new balls and huge 'high MOI' drivers, bogey golfers are hitting bunkers that were never intended for their skill level, while the scratch players are easily carrying bunkers and hazards.

So it's very much depending on the actual changes AND the skill level of any given player, if a change to the course layout will mean an easier or a harder course.

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//Mox
2008 bag:
Mizuno MX-500 460cc 10.5* Fujikura Tour Platform 26.3 stiff. (about to be replaced by MP-600 10,5* UST Proforce V2 stiff)
Mizuno F-50 3w 15* Fujikura Tour Platform 26.3 stiff.
Wilson Deep Red 5w 18* Graphalloy Fatshaft stiff
Cleveland HALO 3i hybrid 22* graphite regular
Mizuno MP-60e forged 5i-PW True Temper Dynamic gold R300 steel
Mizuno MP Black OX raw haze 50/6 GW, 54/9 SW, 58/10 LW
Heavy Putter B3-M
Titleist NXT Extreme