Some brief background for those who have not played: each power in City of Heroes gets enhancement slots. You can fill these to improve various aspects of a power, such as its accuracy, damage, endurance cost, range, etc. Damage is king, so most damage powers get fully slotted with damage, or else one accuracy and the rest in damage. If you are a defensive class, you throw most of your slots into damage resistance or defense.
The obvious effect is to reduce damage, damage resistance, and defense. It will also reduce the top speed of all travel powers, eliminate perma-Hasten (all your powers come back faster), and reduce the endurance recovery of most heroes (6-slotted Stamina is pretty standard). Oh and heals, those will be weaker, too.
The change is named, “Enhancement Diversification.” This is an interesting way of increasing diversity, in that it provides no new options for the players, just making the most popular options worse. With one single, elegant change, it nerfs every popular way to build a character and punishes any attempt to specialize. While there are a few powers that people only two-slot or already slot diversely, this will hit everyone on almost every power that they considered worth slotting. It reduces everyone’s ability to do anything. Healers heal less, tanks take more damage, buffers have weaker buffs, debuffers have weaker debuffs, all damage dealers do less, and everyone spends more time waiting around for endurance because all the recovery powers were weakened in one fell swoop.
And this is before we even get numbers or a chance to try it on the test server. The only question is how severe of a nerf it will be.
In parting, I should toss in the line from the announcement that many have mentioned in the ~3000 posts (and climbing!) that follow it: “Your questions and comments will help refine the patch notes so that we can make this new system as clear as possible for all players.” This is not a request for feedback. Your comments and questions will help them explain this better.