I've had limited experiance with sonics but from what I've heard the 2 mez attacks, sirens song and screech, are very good. So if you want to be more controllerish then they may be worth trying to fit in. I'd possible go with the 3 dmg'ing blast attacks of shriek, scream and shout, then the controlling powers of sirens and screech. Should be able to solo fairly well. With a mob sleeping you can pick them off one by one, open up with a screech so the first woken up minion is disorientated, I can see it working well. You also have the sleeping mob there kept in place in case you need to use an emergency transfusion/transference etc.
If you don't plan on PvPing much, with running 3 slotted tactics you should only need 1 acc enhc in powers.. I have 3 slotted tactics and only have 1 acc in my powers and rarely miss.. its only the occasional stacked vengeance nemesis that give me problems.
I'm going to be going with a kin/sonic once I get Tufty (dark/dark) to lvl 50 so be interested to see how it works out as I think its a fairly unique combination 
You don't need stamina after transferance. Respec it out.
Fulcrum Shift: drop the end reduction, change to accuracy
Transferance: 2 end modification is more than enough to get you filled up again. Add a 2nd recharge instead
May want an extra acc in siphon speed & siphon power.
My idea for my kin defender is as few toggles as possible, toggles can be dropped and are dropped often.
I have both inertial reduction and superjump and I'm loving the combination!
Perhaps, a bit pvp wise, add a slow in siphon speed?
Don't know sonics!
G-Force
On my Kineticist I got by perfectly well without Leadership and Superjump. Inertial Reduction can be perfectly safe, you just set it to autofire.
I'd suggest if you really want Leadership, don't take it until you hit 26, then respec it in. Running that many toggles before then can be lethal. Endurance only stops being a problem when you hit 26/27. It's still a problem for me if Transference misfires (someone will always kill your anchor when you need it most) or it misses.
Other than a bit of strange slotting (as others have pointed out), it's fine IMHO
In my seemingly neverending bid to find an AT and build that I'm happy with (Since Ed in i3 of course *reminisces*), I rolled a Kinetics / Sonic Defender last night and played through to 6. I'm enjoying it, though (as always) lamenting the low level whiffs and the fact that I chose Science as my origin and have been fighting Vaz! >_<
+DMG -RES seems like a good mix to me!
Anyhoo, this is what I've come up with up to 41. I'm thinking that I'm too heavily loaded with accuracy post 31 (Tactics) but I can swap them out for either recharge reduction or endurance reduction (More likely recharge seeing as how I'm not aiming for Hasten and I think I'll have few End worries post-Transference).
I'm also a little concerned at leaving Inertial Reduction so late, but not sure how I can get it into the build earlier. :/
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Exported from Ver: 1.7.5.0 of the CoH_CoV Character Builder
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Name: Sonic Shift
Level: 41
Archetype: Defender
Primary: Kinetics
Secondary: Sonic Blast
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01) --> Transfusion==> Acc(1)Acc(3)Heal(3)Heal(5)Heal(5)Rechg(7)
01) --> Shriek==> Acc(1)
02) --> Scream==> Acc(2)Acc(7)Dmg(11)Dmg(15)Dmg(17)Rechg(19)
04) --> Siphon Power==> Acc(4)Rechg(9)Rechg(23)
06) --> Siphon Speed==> Acc(6)Rechg(9)Rechg(34)
08) --> Combat Jumping==> Jump(8)
10) --> Howl==> Acc(11)Dmg(13)Dmg(15)Dmg(17)Rechg(19)
12) --> Speed Boost==> EndMod(12)EndMod(13)EndMod(23)
14) --> Super Jump==> Jump(14)
16) --> Swift==> Run(16)
18) --> Hurdle==> Jump(18)
20) --> Stamina==> EndMod(20)EndMod(21)EndMod(21)
22) --> Acrobatics==> EndRdx(22)EndRdx(25)EndRdx(37)
24) --> Assault==> EndRdx(24)EndRdx(25)EndRdx(40)
26) --> Transference==> Acc(26)Acc(27)EndMod(27)EndMod(29)EndMod(29)Rechg(31)
28) --> Increase Density==> DmgRes(28)
30) --> Tactics==> TH_Buf(30)TH_Buf(31)TH_Buf(31)
32) --> Fulcrum Shift==> Acc(32)Acc(33)Rechg(33)Rechg(33)Rechg(34)EndRdx(34)
35) --> Shout==> Acc(35)Acc(36)Dmg(36)Dmg(36)Dmg(37)Rechg(37)
38) --> Dreadful Wail==> Acc(38)Acc(39)Dmg(39)Dmg(39)Dmg(40)Rechg(40)
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01) --> Sprint==> Run(1)
01) --> Brawl==> Acc(1)
01) --> Vigilance==> Empty(1)
02) --> Rest==> Rechg(2)
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I know I'm fairly light on attacks, but the build will be more team oriented anyway.
I'll fit Inertial Reduction in at some point, but I wanted the Jump pool for Acrobatics to keep myself mobile against mezzing mobs.
Any thoughts or suggestions? Thanks. ^_^