Looking at your defender build:
1. I would take Freeze Ray over Time Stop... because: Freeze Ray has less activation time and costs less endurance. Sure Time Stop has a -regen component, but it's actually very small in the grand scheme of things.
2. Not a fan of Dark Mastery but I see why you took it... for the aoe.
3. Bitter Ice blast...instead of the 2 ToHit Debuff set enhancements.. put in the other 2 Thunderstrike... You want as much ranged defense you can get...even if it means going over soft cap because you have no defense debuff resistance. The 2% damage increase from those is not going to change your dps really. Time's Juncture provides you with plenty of tohit debuff
My only concern is your melee defense... 31% can be tricky to pull off a lot of melee moves. I am assuming you plan on opening with your ranged attacks and then using aoes to finish your chain.
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Corruptor Build
Basically the same things as above.
Also let me state this... because I always do. I have been building my builds without PVP or Purple IOs... because I have a feeling they are going to be VERY scarce for quite some time. I do have Purple/PVP builds but for now I am sticking to builds without those... I want builds that are maximized without those for when CoH comes back
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So I did two builds... I already have an Ice/Time Build but I noticed you liked Blizzard (I don't because last thing I want are my toggles dropping) and I noticed you like hover... So I did one with Blizzard...and one with Hover. Feel free to pick and choose anything you like from either build.
Thanks for taking the time to look over my builds and giving me some things to think about.
Let me tell you why I made some of the decisions I did.
1. I was thinking Time Stop over Freeze Ray specifically because of the -Regen and the -Heal on it. It's the -Heal that might be sneaky good with it coming in at -37.25% on the Defender. I thought that made it intriguing enough to make that the choice.
2. Personally I really like the Dark Mastery set. For this character it's the end regain (which times almost perfectly with Blizzard), the pbaoe stun for minions, and the oops power in Soul Transfer (love a self rez with a mag 30 stun in it) that really make the difference. Adding those to the resistances and plus damage/acc and it's got most everything I want, except some status protection.
I do agree that both Soul and Power masteries are very strong options.
3. I see your point with BiB. I think I'll change that.
As to the 31% melee D, it won't matter for most environments (I don't know about Incarnate content though). Time's Juncture covers this hole very well and if they are resistant to that I have backup in Oppressive Gloom and it's stuns. Furthering the fun is that getting mobs to -100% on run speed and recharge is very simple and will happen most of the time. Hover speed is 38 MPH and TP if all else fails to get me out of trouble.
As I stated before, I had a Defender version near the end of the game and got him to 50 (but not incarnated nor finished with the IOs) and he was a serious contender for my best tank (Dark Watcher and Deflated Ego have procs that are amazing for taunting). Tanks had to pull mobs off me with their taunt powers.
I even gave thought to going Time/Ice/Mu and taking Provoke.
Oh, and I agree with your stance on Purple IOs, but I was going crazy trying to get perma Ice Storm when I made these.
Changing those out with more affordable options only adds about a half second to recharge on Ice Storm, so ... I'll take the money and run. Good call.
I looked over your builds and it looks like you are going to be taking more of a ranged approach. For some reason (recharge), I don't like PBU quite as much as a lot of other people do.
Great builds though, just not quite the in your face style I want for this guy.