I initially planned to build my Rad/Mental with ranged defense, use EHaze and PScream and Neutron Bomb for AoE, and just dart in and out of melee to use Drain Psyche and PSW and Irradiate. In other words, my build concept looked a lot like yours.
But after playing it for 47 levels, I was pretty sure that Rad/Mental had more potential as a PBAoE blapper in light of Drain Psyche, Irradiate, PSW, Neutron Bomb and Atomic Blast. So I built mine for softcapped S/L defense instead of ranged.
If you go with ranged defense, leaving out EHaze seems like a bad idea; that and PScream and Neutron Bomb would be your AoE damage from range. Irradiate, PSW and World of Confusion are impractical powers for a ranged defense build, since being in melee range to use them consistently basically invalidates all the defense you've built for. And speaking from experience, darting in and out of melee range will still get you hurt and, worse, will detract from your ability to just spam hellacous damage.
I don't mean to be harsh, but your build's a little bit schizophrenic. It really wants to be at range but it really wants to be up close but it really NEEDS to be at range but it absolutely NEEDS to get in close.
Here's a look at my build. It can't solo everything at +2x8 or above, but it can do a lot of stuff at that difficulty. Can do Council Empire at +4x8. Solo farms like a champ. And on teams it's usually the top damage-dealer. The object of my build is to get into melee range with WoC running, hit Drain Psyche for a big buff, and then go to town spamming Irradiate, PSW and Neutron Bomb. If I hit enough foes with Drain Psyche, I can nuke with Atomic Blast, immediately retoggle (often, only one or two of the toggles will actually crash), and then just keep on fighting. I have a few single-target attacks also since they're occasionally useful. 
Code:
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The effects of PBAOEs like Irradiate and PSW (and Drain Psyche) are a sphere, not a disk, so it's more than possible to rely on ranged defense if you've got a good enough eye to pop them from above. Out of melee reach, but within your pbaoe sphere.
It's tricky, but viable, and ranged defense when you can avoid melee range entirely covers more stuff than S/L defense does.
That'll work ok for Irradiate and PSW which have 20' and 15' radii respecively, but less effectively for Drain Psyche and World of Confusion which have radii of 10' and 8' respectively. Even for the 20' and 15' spheres, coverage is significantly reduced if two thirds of the PBAoE volume is above the mobs and empty.
I imagine it's viable to hover above mobs where possible and use Irradiate and PSW, like you said, and that it's safer that way, but that it's not always possible to do this (low ceilings), and even when it is, you're still giving up AoE output when the volume of your spheres is mostly empty and the lower third isn't saturated.
But whatever works for you. As I explained above, the S/L defense, PBAoE blapper concept works extremely well for me.
Couple people asked me about my build and I told them I'd post it online. Here is what I plan on doing with my newest blaster - Rattux.
Hero Plan by Mids' Hero Designer 1.601
http://www.cohplanner.com/
Rattux: Level 50 Magic Blaster
Primary Power Set: Radiation Blast
Secondary Power Set: Mental Manipulation
Power Pool: Fitness
Power Pool: Speed
Power Pool: Leaping
Power Pool: Flight
Ancillary Pool: Flame Mastery
Hero Profile:
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Level 1: Neutrino Bolt Thundr-Acc/Dmg(A), Thundr-Dmg/EndRdx(3), Thundr-Dmg/Rchg(3), Thundr-Acc/Dmg/Rchg(5), Thundr-Acc/Dmg/EndRdx(5), Thundr-Dmg/EndRdx/Rchg(7)
Level 1: Subdual Thundr-Acc/Dmg(A), Thundr-Dmg/EndRdx(15), Thundr-Dmg/Rchg(25), Thundr-Dmg/EndRdx/Rchg(27), Thundr-Acc/Dmg/Rchg(42), Thundr-Acc/Dmg/EndRdx(48)
Level 2: X-Ray Beam Thundr-Acc/Dmg(A), Thundr-Dmg/EndRdx(7), Thundr-Dmg/Rchg(9), Thundr-Acc/Dmg/Rchg(9), Thundr-Acc/Dmg/EndRdx(11), Thundr-Dmg/EndRdx/Rchg(11)
Level 4: Irradiate Oblit-Dmg(A), Oblit-Acc/Rchg(15), Oblit-Dmg/Rchg(33), Oblit-Acc/Dmg/Rchg(33), Oblit-Acc/Dmg/EndRdx/Rchg(34)
Level 6: Hurdle Jump-I(A)
Level 8: Hasten RechRdx-I(A), RechRdx-I(13), RechRdx-I(13)
Level 10: Psychic Scream Posi-Acc/Dmg(A), Posi-Dmg/EndRdx(17), Posi-Dmg/Rchg(17), Posi-Dam%(23), Posi-Acc/Dmg/EndRdx(25)
Level 12: Aim GSFC-ToHit(A), GSFC-ToHit/Rchg(27), GSFC-ToHit/Rchg/EndRdx(29), GSFC-Rchg/EndRdx(29), GSFC-ToHit/EndRdx(31), GSFC-Build%(31)
Level 14: Super Speed Zephyr-Travel(A), Zephyr-Travel/EndRdx(50)
Level 16: Health Numna-Regen/Rcvry+(A), Mrcl-Rcvry+(31)
Level 18: Cosmic Burst Thundr-Acc/Dmg(A), Thundr-Dmg/EndRdx(19), Thundr-Dmg/Rchg(19), Thundr-Acc/Dmg/Rchg(21), Thundr-Acc/Dmg/EndRdx(21), Thundr-Dmg/EndRdx/Rchg(23)
Level 20: Stamina P'Shift-EndMod(A), P'Shift-EndMod/Rchg(40), P'Shift-EndMod/Acc/Rchg(40)
Level 22: Concentration AdjTgt-ToHit/Rchg(A), AdjTgt-ToHit/EndRdx/Rchg(33), AdjTgt-EndRdx/Rchg(34)
Level 24: Drain Psyche Nictus-Heal/HP/Regen/Rchg(A), Nictus-Acc/EndRdx/Heal/HP/Regen(34), Nictus-Acc/EndRdx/Rchg(36)
Level 26: Neutron Bomb Posi-Acc/Dmg(A), Posi-Dmg/EndRdx(36), Posi-Dmg/Rchg(36), Posi-Dam%(37), Posi-Acc/Dmg/EndRdx(37)
Level 28: Proton Volley Mantic-Acc/Dmg(A), Mantic-Dmg/EndRdx(37), Mantic-Acc/ActRdx/Rng(39), Mantic-Dmg/ActRdx/Rchg(39), Mantic-Dmg/EndRdx/Rchg(39)
Level 30: World of Confusion CoPers-Conf(A), CoPers-Conf/Rchg(45), CoPers-Acc/Conf/Rchg(46), CoPers-Acc/Rchg(46), CoPers-Conf/EndRdx(46), CoPers-Conf%(48)
Level 32: Combat Jumping Zephyr-Travel(A), Zephyr-ResKB(42), LkGmblr-Rchg+(43)
Level 35: Hover Zephyr-Travel/EndRdx(A), Zephyr-Travel(43), LkGmblr-Rchg+(50)
Level 38: Psychic Shockwave Oblit-Dmg(A), Oblit-Acc/Rchg(40), Oblit-Dmg/Rchg(43), Oblit-Acc/Dmg/EndRdx/Rchg(45), Oblit-Acc/Dmg/Rchg(45)
Level 41: Char BasGaze-Acc/Hold(A), BasGaze-Acc/Rchg(42)
Level 44: Super Jump Zephyr-Travel(A), Zephyr-Travel/EndRdx(48)
Level 47: Fly Zephyr-Travel/EndRdx(A), Zephyr-Travel(50)
Level 49: Fire Shield S'fstPrt-ResDam/Def+(A)
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Level 1: Brawl Empty(A)
Level 1: Sprint Clrty-Stlth(A)
Level 2: Rest Empty(A)
Level 1: Defiance
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Set Bonus Totals:
17.5% DamageBuff(Smashing)
17.5% DamageBuff(Lethal)
17.5% DamageBuff(Fire)
17.5% DamageBuff(Cold)
17.5% DamageBuff(Energy)
17.5% DamageBuff(Negative)
17.5% DamageBuff(Toxic)
17.5% DamageBuff(Psionic)
4.25% Defense(Smashing)
4.25% Defense(Lethal)
4.25% Defense(Fire)
4.25% Defense(Cold)
33% Defense(Energy)
33% Defense(Negative)
3% Defense(Psionic)
5.5% Defense(Melee)
44.3% Defense(Ranged)
5.5% Defense(AoE)
4% Enhancement(Confused)
55% Enhancement(RechargeTime)
73% Enhancement(Accuracy)
26% FlySpeed
67.8 HP (5.62%) HitPoints
26% JumpHeight
26% JumpSpeed
Knockback (Mag -4)
Knockup (Mag -4)
MezResist(Stun) 4.4%
19.5% (0.33 End/sec) Recovery
12% (0.6 HP/sec) Regeneration
3.15% Resistance(Fire)
3.15% Resistance(Cold)
1.26% Resistance(Energy)
1.26% Resistance(Negative)
26% RunSpeed