Rad/Pain won't be a damage dynamo, but you'll have solid-to-awesome debuffs, decent heals, and decent buffs to throw around. Conduit of Pain is a risky way to give yourself a sweet little damage boost, and you can use it solo if you have a targetable pet (Like the Blue Whisp or the Power Oscilator) from your VIP awards.
From what I've heard, the Regen Toggle is next to useless on corruptors.
I've played /Pain into the mid-20s before deciding it wasn't my thing, but please don't let that dissuade you. Lv 50 /Pain Corrs can do some dangerous things and help keep parties alive through nasty stuff.
Too many alts to list.
I've got a Dark/Pain corr and also a Rad/Thermal, both lvl 50 with IOs and Incarnate powers etc.
Soothing Aura is not that bad. I agree it's one of the most skippable powers in the set, but if you properly slot it, for a minimal end cost you can constantly heal yourself without interrupting your attack chain.
Rad/ has a PBAoE and an AoE that you can use point blank, and Anguishing Cry from /Pain is a PBAoE debuff, so all of these powers have a certain synergy: jump into melee, debuff your enemies and infect them with your AoE while healing melee ATs without even thinking of it.
Since my Dark/ corr stays at range to use her cones, I went with Dark Mastery but for a Rad/ one who would stay in melee, I would suggest Mace Mastery and S/L softcap. Rad AoEs and Cosmic Burst are quite slooooow, so a big chunk of defense is always nice to keep oneself alive.
I really don't like Radiation Blast on corr. The only thing great about the whole set is Cosmic Blast.
/Pain Domination is ok. It's better for a larger team (world of pain) than soloing or small team.
What's left is to normalize all Assassin Strikes and improve Stalker's old sets (Claw, MA and EM)! You don't need to bring back the missing PbAoE attack. You just need to make the existing ones better! For example, make Slice a WIDER and LONGER cone.
...last night based on an idea I had yesterday on my way to work. This will be my second Corruptor; my first is a Dark Blast / Dark Miasma. For this build, I went with Radiation Blast / Pain Domination. I have never used these two powers together before. I was wondering if any Corruptors players have used this combination. Was it a good choice or did I make a big booboo! lol (I'm branching out into using support toons for more challenges and enjoyment, then being strictly a melee specialist for the most part.
Current active characters: Dragon Maiden (50+3 Brute SS/WP/PM), Black Widow Maiden (50+1 Night Widow), Catayclasmic Ariel (50 lvl Defender - Kin/DP), Quantumshock (50 lvl Elect/Energy/Energy), American's Defender (38 lvl Tanker - SD/Mace), Spider-Maiden (15 lvl Corruptor - RB/PD) & Siren Shrike (15 lvl Defender - Sonic/Sonic). My entire stable.