I'm not a PvP or a stalker expert but couple of things I think should be changed...
1) Swap Mu patron for Scorpio, the hold has -fly (and maybe -jump too?) which is nice in PvP.
2) AS, 3 damage which I think is what you meant instead of 3 acc 
3) 2 acc in all attacks or a set.
4) You might want to move 3rd speed and a heal from health to ToHit in BU.
5) If you're not only PvPing in RV get stealth earlier 
- @DSorrow - alts on Union and Freedom mostly -
Currently playing as Castigation on Freedom
My Katana/Inv Guide
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. -Einstein
Unless IO'd you dont need Health. You also need Hide slotted ASAP with 3 def 2 end, if you plan to pvp.
From what I can tell at a quick look
1. Dont need int.red in AS, 2 acc 3 dam and a endrdx or rch will do you fine
2. Guess you wanna pvp with this build, so yeh as Zaldor said, leave out health, pick a different patron, and figure out where you wanna pvp.
3. You said you were taking stealth at 30, good choice.
4. Would take Bone Smasher earlier and Focused Senses later. At early lvl, its better to get through them faster with greater damage output, than to have more defence, as you lvl up, and take on harder stuff, this then becomes more important. This is just for a lvling up point of view. On my /SR i took senses at 24.
5. As said before, min of 2 acc in each attack.
6. For PvE you dont need the extra slots in SS or hurdle really.
7. Take Build up earlier, helps enourmously in the low lvls.
8. Slot Hide up for def with any spare slots. Helps with your aoe and cone defence.
Just remember, slot for acc first, then damage then rch or end red in attacks.
Slot for endrdx in shields first, then def.
And Elude, slot for rch, then def.
Have fun with it.
Yeah I don't know what happened with AS slotting there, either I clicked it wrong or it bugged.. but I meant to have 3 damage :P
And also, I said I would fit stealth in at 30, and it was a mistake 
Also, dont even bother with Mu patron. Take Scorpion if you want pvp in RV, elsewhere dont take one at all, they suck massively.
Mako is sexeh too
Been thinking about rolling an EM/SR Stalker, thought I'd ask for build advice here
This is a quick one I have come up with... (Edit- Stealth meant to be fitted in at 30)
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Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder
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Name:
Level: 50
Archetype: Stalker
Primary: Energy Melee
Secondary: Super Reflexes
---------------------------------------------
01) --> Energy Punch==> Dmg(1)Dmg(15)Dmg(15)Acc(19)EndRdx(34)
01) --> Hide==> EndRdx(1)
02) --> Focused Fighting==> DefBuf(2)DefBuf(3)DefBuf(3)EndRdx(7)EndRdx(43)
04) --> Focused Senses==> DefBuf(4)DefBuf(5)DefBuf(5)EndRdx(7)EndRdx(43)
06) --> Assassin's Strike==> IntRdx(6)Dmg(11)Dmg(11)Acc(19)Acc(40)Acc(43)
08) --> Hasten==> Rechg(8)Rechg(9)Rechg(9)
10) --> Hurdle==> Jump(10)Jump(50)Jump(50)
12) --> Placate==> Rechg(12)Rechg(13)Rechg(13)
14) --> Super Speed==> Run(14)Run(46)Run(48)
16) --> Practiced Brawler==> Rechg(16)Rechg(17)Rechg(17)
18) --> Health==> Heal(18)Heal(50)
20) --> Stamina==> EndMod(20)EndMod(21)EndMod(21)
22) --> Bone Smasher==> Dmg(22)Dmg(23)Dmg(23)Acc(31)EndRdx(31)Rechg(37)
24) --> Build Up==> Rechg(24)Rechg(25)Rechg(25)
26) --> Energy Transfer==> Dmg(26)Dmg(27)Dmg(27)Rechg(29)Acc(29)EndRdx(31)
28) --> Quickness==> Run(28)
30) --> Stimulant==> Empty(30)
32) --> Total Focus==> Dmg(32)Dmg(33)Dmg(33)Acc(33)Rechg(34)EndRdx(34)
35) --> Aid Self==> Heal(35)Heal(36)Rechg(36)Rechg(36)IntRdx(37)IntRdx(37)
38) --> Elude==> DefBuf(38)DefBuf(39)DefBuf(39)Rechg(39)Rechg(40)Rechg(40)
41) --> Zapp==> Dmg(41)Dmg(42)Dmg(42)Acc(42)
44) --> Electric Shackles==> Hold(44)Hold(45)Acc(45)Acc(45)Rechg(46)Rechg(46)
47) --> Dodge==> DefBuf(47)DefBuf(48)DefBuf(48)
49) --> Stealth==> EndRdx(49)
---------------------------------------------
01) --> Sprint==> Run(1)
01) --> Brawl==> Acc(1)
01) --> Assassination==> Empty(1)
02) --> Rest==> Rechg(2)
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