Fire/Rad was smoothest ride to 50 I've ever had. You can definitely bring the damage, while usually not worrying about defenses. I took Fire Breath while leveling, then respecced out. But I'd definitely take Fire Rain, the bigger rad(ius) over Ground Zero shows up a lot. Likewise, Blazing Blast does solid damage, I'd rather drop Fire Blast. It's useful when you get Boss aggro. Didn't take any Epic pools.
It's the only toon I didn't bother to softcap because stuff is almost always dead before I'm in trouble. The Absorb is a big deal. Focused on extra damage instead, plus Fly and Afterburner as a luxury. Wouldn't be hard to soft cap if you give up a few things, but I don't miss it. More fun to just melt everything.