Triviate, your build is similar to mine, and mine's working real well.
Here's mine:
Archetype: Defender
Primary Powers - Buff/Debuff : Radiation Emission
Secondary Powers - Ranged : Dark Blast
Slot[01] Level 1 (Starting Primary) : Radiation Infection /HitDeb,HitDeb,HitDeb,DefDeb,DefDeb,DefDeb
Slot[02] Level 1 (Starting Secondary) : Dark Blast /Dmg,Dmg,Dmg,Dmg,Dmg,Dmg
Slot[03] Level 2 : Gloom /Dmg,Dmg,Dmg,Dmg,Dmg,Dmg
Slot[04] Level 4 : Moonbeam /Dmg,Dmg,Dmg,Dmg,Dmg,Dmg
Slot[05] Level 6 : Enervating Field /EndRdx,EndRdx,EndRdx
Slot[06] Level 8 : Accelerate Metabolism /Rchg,Rchg,Rchg,Rchg,EndRec,EndRec
Slot[07] Level 10 : Hasten /Rchg,Rchg,Rchg,Rchg,Rchg,Rchg
Slot[08] Level 12 : Lingering Radiation /EndRdx,EndRdx,Slow,Slow
Slot[09] Level 14 : Super Speed /Run
Slot[10] Level 16 : Tenebrous Tentacles /Immob,Immob,Immob,Immob,EndRdx,Rng(Cone)
Slot[11] Level 18 : Hurdle /Jump
Slot[12] Level 20 : Health /Heal
Slot[13] Level 22 : Stamina /EndRec,EndRec,EndRec,EndRec,EndRec,EndRec
Slot[14] Level 24 : Boxing /Dmg
Slot[15] Level 26 : Tough /DamRes,DamRes,DamRes,DamRes,DamRes,DamRes
Slot[16] Level 28 : Weave /DefBuf,DefBuf,DefBuf,DefBuf,DefBuf,DefBuf
Slot[17] Level 30 : Combat Jumping /DefBuf
Slot[18] Level 32 : EM Pulse /Acc,Acc,Hold,Hold,Rchg,Rchg
Slot[19] Level 35 : Super Jump /Jump
Slot[20] Level 38 : Blackstar /Dmg,Dmg,Dmg,Dmg,Dmg,Dmg
Slot[21] Level 41 : Acrobatics /EndRdx
Slot[22] Level 44 : Radiant Aura /Heal,Heal,Heal
Slot[23] Level 47 : Mutation /EndRdx
Slot[24] Level 49 : Swift /Run
Instead of Stealth and Leadership, I took Fighting & Leaping.