I don't know about the damage resistance part, but the cooldowns are longer because the effectiveness of the attributes on your armor has been cut drastically. Gear that previously gave you 100% in a certain stat now only gets you to the equivalent of 40%, and the basic, unboosted cooldowns have all been increased as well, so that 40% reduction is coming off of a longer interval. That has a major effect on Radiance, because that super applies a multiplier to your existing recharge times, and so is greatly affected by your stats. The super will get better when you get some TTK gear and get your cooldowns back closer to what they were before the 2.0 patch. Unless you didn't buy TTK, in which case I'm pretty sure they're trying to make you quit.