I think the new groove rule will have three major effects.
First, even normal rough will now often have a punitive effect. As discussed above, this will put an emphasis, lost these days in any tournament that doesn't grow jungles for rough, back on staying in the fairway.
Second, players with lesser skills that have been propped up by equipment wil start to fall by the wayside.
Third, a premium will once again be placed on shot-making, rather than the drive, wedge, putt that has dominated in recent years. The ability to hit short shots straight has become embarassingly absent from the games of many pros in recent years. Its not that hard to tell that a lot of pros are content to make birdies when their shot randomly drops close to the hole, rather than consciously seeking that result on each approach shot.
I've long maintained that the reason there aren't a larger number of consistent winners on the Tour is that the money is so big that not that many are truly fixated on winning ... the reasoning being that before the absurdly large purses hit, there was much more of a "sink or swim" purpose to the competition for the smaller purses.
Thinking about the equipment angle stated above, I may have to add to the "sink or swim" reasoning. If equipment is propping up some otherwise lesser talents so that they dilute the results of those who are actually more technically proficient in the golf swing, that could also have an effect. I still like my "sink or swim" theory as the primary cause though, just because of the fact that even with modern equipment, there is a LOT of inconsistency out on the Tour. This says that equipment can't be hiding ALL sins of the swing.