Any particular reason why you are forgoing IOs? If it's cost, just frankenslot. I ask because...well, frankly, I cannot see your end bar lasting for very long after conserve energy stops. Human form can be downright nasty on the blue bar, and not only do you have very few end reductions, but you have quite a bit of recharge, too.
Anyhow, Solar Flare is a good power. If you're worried about knockback, you just have to make sure you use it tactically. My advice on your build? IO your character, bring up those enhancement values. Then build for recharge.
Most of the powers you've chosen I wouldn't pick on my humanform--the scatter/detonation powers are too weak for what they cost to use, and with enough recharge solar flare is the better choice for AoE damage. I also wouldn't pick up Glowing Touch, mind you, but that is more of a personal choice, and I won't try to talk you out of that. Indeed, if you're happy with your build, that is all that really matters.
Oh, and I would choose the Cardiac alpha. It will help alleviate any issues that crop up.
No reason I'm not sitting in IO's. Frankly, I just don't know which direction I should lean. Resistance? Recharge? S/L defense?
I'm fairly understanding of scrapper builds and their objectives. I wouldn't say I could build to achieve those objectives but I get the ideas.
I'm going to try some slotting, see how it turns. See if I can bring my regen up for a reasonable price. If nothing else some basic IO's will net me competent power effects.
If you don't mind, Daemon, pm me.. let me know what you wouldn't take and what you'd take for it. I'm curious what other people lean into for their human builds. Kheldian is one of those AT's that it isn't about your powerset but about which powers you pick up.
I can see where you might not take Glowing Touch, it's a support power, a Sit Back and Wait power. I'm tempted not to take it either as I'm more of a do'er and less interested in support. But I also understand where it could be handy to pack a little something for the team in those tight spots.
Life is pleasant. Death is peaceful. It's the transition that's troublesome.
Isaac Asimov
Since the most recent round of changes Recharge really is the way to go. You're aiming for perma Light Form and perma Inner Light. Spiritual is obviously helpful for this but it can be accomplished without assistance from the Alpha Slot so Musculature is a viable option.
Once you've got that handled a lot of Human only builds look to softcap their Defense. Being a TriFormer (And someone who doesn't have the energy for that kinda optimization 
) I didn't bother but there's no denying that having capped Resistance and Defense makes you about as close to godlike as you can get.
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PEACEBRINGERS SUCK!!! (Now fully up to date for i21+
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So I'm working out a build for a PB, I have a pretty basic slotting figured out for some general play and leveling up. Most of my power choices are aligned with teaming in mind. Solar Flare is a prime example of a power that I find fun, but generally not useful in the grand scheme.
I use a conventional rotation of Glinting Eye, Gleaming Blast, Luminous Detonation and Proton Scatter with a sprinkling of Photon Seekers as needed. I dash with Radiant Strike and the very awesome "Now you DIE mister Void!" Incandescent Strike. Glowing Touch is there for helping out where needed or tight battles.
What I don't know is the easy or better direction to lean with set bonuses the good choice. So far it plays pretty well and I'm happy as a clam at 33.
Any thoughts or suggestions you could provide would be immensely helpful.
As a sub-query, would I get decent mileage out of Musculature or is the Alpha Recharge better off?
Thank you all very much in advance.
Hero Plan by Mids' Hero Designer 1.952
http://www.cohplanner.com/
Click this DataLink to open the build!
Sentinel Solar: Level 50 Natural Peacebringer
Primary Power Set: Luminous Blast
Secondary Power Set: Luminous Aura
Power Pool: Speed
Power Pool: Fighting
Power Pool: Leadership
Hero Profile:
Level 1: Glinting Eye -- Dmg-I(A), Dmg-I(3), Dmg-I(3), Acc-I(5), RechRdx-I(5)
Level 1: Incandescence -- ResDam-I(A), ResDam-I(7)
Level 2: Shining Shield -- ResDam-I(A), ResDam-I(7), ResDam-I(9), EndRdx-I(9)
Level 4: Gleaming Blast -- Dmg-I(A), Dmg-I(15), Dmg-I(15), Acc-I(17), EndRdx-I(17)
Level 6: Essence Boost -- Heal-I(A), Heal-I(19), RechRdx-I(19), RechRdx-I(21)
Level 8: Radiant Strike -- Dmg-I(A), Dmg-I(21), Dmg-I(23), Acc-I(23), EndRdx-I(25)
Level 10: Hasten -- RechRdx-I(A), RechRdx-I(11), RechRdx-I(25)
Level 12: Inner Light -- RechRdx-I(A), RechRdx-I(27)
Level 14: Luminous Detonation -- Dmg-I(A), Dmg-I(27), Dmg-I(29), Acc-I(29), EndRdx-I(31)
Level 16: Quantum Shield -- ResDam-I(A), ResDam-I(31), ResDam-I(33), EndRdx-I(33)
Level 18: Incandescent Strike -- Dmg-I(A), Dmg-I(33), Dmg-I(34), Acc-I(34), EndRdx-I(34)
Level 20: Boxing -- EndRdx-I(A)
Level 22: Reform Essence -- Heal-I(A), Heal-I(36), Heal-I(36), RechRdx-I(36), RechRdx-I(37)
Level 24: Conserve Energy -- RechRdx-I(A), RechRdx-I(37)
Level 26: Proton Scatter -- Dmg-I(A), Dmg-I(37), Dmg-I(39), Acc-I(39), EndRdx-I(39)
Level 28: Tough -- ResDam-I(A), ResDam-I(31), ResDam-I(40), EndRdx-I(50)
Level 30: Weave -- DefBuff-I(A), DefBuff-I(40), DefBuff-I(40), EndRdx-I(48)
Level 32: Photon Seekers -- Dmg-I(A), Dmg-I(42), Dmg-I(42), RechRdx-I(42), RechRdx-I(43), EndRdx-I(43)
Level 35: Glowing Touch -- Heal-I(A), Heal-I(43), RechRdx-I(45), EndRdx-I(45)
Level 38: Light Form -- RechRdx-I(A), RechRdx-I(45), RechRdx-I(46), ResDam-I(46)
Level 41: Restore Essence -- RechRdx-I(A)
Level 44: Maneuvers -- DefBuff-I(A), DefBuff-I(46), DefBuff-I(48), EndRdx-I(48)
Level 47: Tactics -- EndRdx-I(A), EndRdx-I(50)
Level 49: Quantum Acceleration -- Flight-I(A), Flight-I(50)
Level 0: Portal Jockey
Level 0: Task Force Commander
Level 0: The Atlas Medallion
Level 50: Spiritual Core Paragon
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Level 1: Brawl -- Empty(A)
Level 1: Cosmic Balance
Level 1: Energy Flight -- Flight-I(A)
Level 1: Sprint -- QckFt-EndRdx/RunSpd(A)
Level 2: Rest -- Empty(A)
Level 4: Ninja Run
Level 10: Combat Flight -- DefBuff-I(A)
Level 2: Swift -- Run-I(A)
Level 2: Health -- Heal-I(A), Heal-I(11)
Level 2: Hurdle -- Jump-I(A)
Level 2: Stamina -- EndMod-I(A), EndMod-I(13), EndMod-I(13)
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Life is pleasant. Death is peaceful. It's the transition that's troublesome.
Isaac Asimov