Looks like you forgot about "Enhancement Diversification".
Since i6, slotting more than 3 of any type of enhancement in your powers is a waste. You might want to try out Mid's Hero builder, it'll give you a far better idea of what slotting different things (like IOs!) will do.
If you're using SOs:
+ Minion Robots should be 2-3acc/3dmg.
+ LTs should be 2acc/3dmg/1endred (uses lots of end after the level 32 upgrade).
+ Boss Robot should be 1-2acc/3dmg.
+ Bubbles should be 3 defence + (Optional) 1 endred.
+ Dispersion Bubble should be 3 defence/3 endred.
+ Equip Robot only needs a single endred.
+ Upgrade Robot only needs 1-2 recharge, 1-2 endreds.
+ Detention field needs at least one accuracy.
+ MM's Personal Forcefield has a looooooong recharge time. Might want 3 recharges in there.
Aside from the slotting, it's not a bad build. I only have a few pointers about power picks:
+ Repulsion Bomb is generally thought of as a rubbish power, will scatter mobs a LOT and annoy teammates.
+ Get Swift instead of Hurdle if you're using the Flight pool. You can slot Swift with a +Fly SO and this will free up slots in "Fly" itself. IIRC one Fly SO in Swift and 2-3 in Fly will hit the flight speed cap.
+ Repair is not as good as Aid Other. You'd get far better milage from "Aid Other", as it recharges faster and can be used on teammates. It would also open up the way for you to get the self-heal "Aid Self".
+ You'll probably want to take recall friend. Bot AI isn't too bad, but quite often one will end up getting stuck in the geometry and need TP'ed out or resummoned.
+ You don't need to take stamina for a /FF, so that could free up another pool for you. I like the leadership pool on my masterminds, but that's really down to personal choice. Definately get Aid Other though! 
I'd probably suggest the Black Scorpion patron pool since the +defence shield will stack with dispersion bubble. The Black Scorpion AoE Immobilise/-jump/-fly is also very useful for stopping foes running and keeping minions clustered together for your Assault Bot's burn patch missiles. And it's lovely in PvP... 
Oh, yes, the ED-thing is really bad. Always remember: Never slot a power with more than three SOs of a kind.
Basically I agree with Maelwys. Just a few additions:
+ Please, don't 3-slot Stealth powers for defense. The defense bonus is negligible even for a bubbler and on top of that invisibility would only help you in PvP (for a nice gimmick effect) and do little good in PvE since the robots will eventually be quite adept at annihilating enemy spawns and you definitely don´t want to stealth missions. Being able to defeat "normal" mobs in minimum time is one of the biggest strengths of the MM.
+ Because of robots' already mentioned knack for total annihilation Detention Field will probably be more of a self-debuff than anything else. In most cases your robots will have defeated the whole spawn within 15 seconds. So, all this power does is that you have to wait longer, because your pets can't harm a detentioned mob.
Depending on your team this power has some use when you are facing an AV in a troublesome spawn or even multiple AVs (which will not happen before the 40ies), but chances are that it will annoy your teammates roughly as often as it may actually help in these situations. So, if you want this power make sure you only use it in appropriate situations.
+ As Maelwys hinted, Leadership is almost a must for a MM. Why did I say "almost"? It is. You will profit from Assault+Tactics, especially since your secondary powerset offers no debuffs and only defensive buffs.
If it has eyes, you can blind it, if it has blood, you can make it bleed, if it has a mouth, you can make it scream.
Do you plan to use this mainly for PvP, mainly for PvE or so that it can do a reasonable job at both?
My thoughts on this :
Battle Drones==> Acc(1) Acc(3) Dmg(3) Dmg(7) Dmg(7) Dmg(9)
At high levels the Drones are your level -2 so they do need a bit of extra accuracy.
3xAcc and 3xDmg are good here.
Protector Bots==> Acc(12) Acc(13) Dmg(13) Dmg(15) Dmg(15) Dmg(17)
The Prot-Bots force fields they give out do give a good amount of defence (7.5%) so some defbufs are very useful here.
I currently have mine slotted 2xAcc, 2xDmg and 2xDefBuf.
After the last upgrade they do start to use a lot of endurance so a EndRed would be handy.
I prefer Aid Other to Repair (although I do have both), it will also enable you to get Aid Self. Very handy at times.
Dispersion Bubble sucks End like you would not believe.
3xEndReds are needed.
The invisibility powers are of only minor use, you would be better off with the leadership pool IMO.
With ED you only get a very small benefit from slotting more than 3 SOs of a certain type in a power.
It isn't worth it.
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Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder
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Name: Full Power MM
Level: 50
Archetype: Mastermind
Primary: Robotics
Secondary: Force Field
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01) --> Battle Drones==> Acc(1)Acc(3)Dmg(3)Dmg(7)Dmg(7)Dmg(9)
01) --> Force Bolt==> Acc(1)Acc(5)Rechg(5)Rechg(9)
02) --> Deflection Shield==> DefBuf(2)DefBuf(11)DefBuf(19)DefBuf(23)
04) --> Insulation Shield==> DefBuf(4)DefBuf(11)DefBuf(19)
06) --> Equip Robot==> EndRdx(6)EndRdx(33)EndRdx(34)
08) --> Hover==> Fly(8)
10) --> Detention Field==> Rechg(10)Rechg(40)
12) --> Protector Bots==> Acc(12)Acc(13)Dmg(13)Dmg(15)Dmg(15)Dmg(17)
14) --> Fly==> Fly(14)Fly(37)Fly(37)Fly(42)EndRdx(43)EndRdx(43)
16) --> Personal Force Field==> DefBuf(16)DefBuf(17)DefBuf(21)
18) --> Repair==> Rechg(18)Rechg(34)Rechg(39)
20) --> Dispersion Bubble==> DefBuf(20)DefBuf(21)DefBuf(23)DefBuf(25)
22) --> Grant Invisibility==> DefBuf(22)DefBuf(25)DefBuf(33)
24) --> Invisibility==> Rechg(24)DefBuf(31)DefBuf(31)DefBuf(40)
26) --> Assault Bot==> Acc(26)Acc(27)Dmg(27)Dmg(29)Dmg(29)Dmg(31)
28) --> Recall Friend==> Empty(28)
30) --> Hurdle==> Jump(30)Jump(37)Jump(40)Jump(42)
32) --> Upgrade Robot==> EndRdx(32)EndRdx(33)EndRdx(34)
35) --> Repulsion Bomb==> Acc(35)Acc(36)KB_Dist(36)DisDur(36)
38) --> Force Bubble==> EndRdx(38)EndRdx(39)EndRdx(39)EndRdx(43)Rechg(46)Rechg(46)
41) --> Health==> Heal(41)Heal(42)
44) --> Stamina==> EndMod(44)EndMod(45)EndMod(45)EndMod(45)EndMod(46)
47) --> Group Fly==> EndRdx(47)EndRdx(48)EndRdx(48)Fly(48)Fly(50)Fly(50)
49) --> Teleport Foe==> Acc(49)Acc(50)
---------------------------------------------
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Supremacy==> Empty(1)
02) --> Rest==> Empty(2)
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