I thought honestly radiation was more offense oriented then dark or time. It wasn't as offense oriented as trick arrows, but it was still fairly offensive. Of the debuff sets I considered trick arrows the most "aggressive" in that it's debuffs for helping team survivability were pretty weak, a to-hit debuff with only 6.25% base, damage debuff at about 25% and a recharge debuff at only 20% were all pretty weak even stacked together. But the sonic and acid arrows were unmatched for resistance debuffing, one of them also killing defense, oil slick arrow was also killer for offense obviously, burn and huge -defense. Then course, EMP arrow was also a powerful AoE control. But TA's early powers were comparatively weak.
Dark was extremely heavily, i'd say protective, as a debuff set, and was kingly at lockdown. Enemies that had floored to hit and were getting hit by crowd control at the same time were largely incapable of hurting teams much. Dark/dark was a hell of a set used by someone who knew what they were doing. I met a few who used dark/dark horribly(litterally just trying to heal people and not debuffing/ccing at all) but used right 8x+4 was a breeze for experts save for archvillains.
I honestly don't tend to grade the buff/debuff sets much anymore since I look at them and I noticed they were pretty balanced. I could think of some weak spots here and there(such as TA's weak early powers or empathy's inability to really scale with a league very well) but most part they were very well able to multiply teammate effectiveness. Just some were better for solo than others.
Trick Arrow had the obvious OSA offensive power, but both Rad and Dark had significant offensive power in their debuffs. In fact while disruption arrow was a -20% res debuff (defender numbers) enervating field and tar patch were both -30%. Until you could stack DA, its debuff was significantly weaker. And Rad had the damage buff *and* recharge buff in AM which both contributed to offense (Rad also had recovery which for earlier levels probably provided a larger boost to offense than anything else).
In actual play, I think TA/* had the most offense, Rad/* second and Dark/* third, but it was closer than many suggested. On the flip side, things closed up even more: */TA, */Rad, and */Dark were much more closely matched as controllers (Rad's buffs become more beneficial with pets around, but its toggles become more tactically clumsy compared to TA and Dark). I think its interesting that while it was difficult to beat Fire/Kin on offense, there was no general consensus on which of Fire/TA, Fire/Dark, and Fire/Rad had the stronger offense. Doubly weird because you could say the same thing about Ill/Dark, Ill/Rad, and Ill/TA even though the dynamics of Illusions are radically different from Fire as they pertain to set synergy with Dark, Rad, and TA.
Both Time/* and */Time were not in the same league as those combinations above when it came to offense, though.