Okay, so I get the wanted to add new +4/+5 exceptional skill items and wanted to avoid too much stacking, ie. players getting +1+2+3 (gs) +4 (some new stuff) +5(some other new stuff)
But why change GS? Had they made the new items to grant say +2 exceptional skill bonus and +2 (or more, depending on item) pumpernickel skill bonus (with only the highest pumpernickel bonus applying), the effects would be similar, except noone would complain about them messing with existing content.
We've all seen what happens when they try to change something - it stops working completely, and three patches later the only way to fix it is to revert to an earlier version.
I think the issue is the mentality, that the replacing old stuff with new stuff is a value in and off itself, and no one cares how useful/valuable the old stuff was and how the new fares in comparison.