I don't have access to Mids (yet, come on new hard drive!) so makes it a bit tougher to comment, but here's some thoughts:
If you are going to use 3 Def IO's in the passives may as well grab some more +max health and +regen ... 3 Serendipity work well here and shouldn't be out of budget. I tend to shoot for at least 1850 Health and 25hp/sec regen on my SR builds. I've found the difference between 1750 health and 1950 or more health (and even more so high teens regen vs near 30hp/sec) very significant even before one adds in things like Rebirth when it comes to survival (and dead scrappers don't do damage).
Not sure what kind of recharge is needed for Spines best attack chains. I personally don't worry too much about chains, team play vs AV hunting/Pylon soloing makes them a bit irrelevant for me as a build concern compared to other goals. Truly high recharge tends to be at odds with my other goals such as getting the health and regen up where I want them and think those are more important when it comes to a teaming/TF/League oriented build. And in Spines especially I'd be more interested in making sure my AoE potential was a priority over single target in any case. Seems like (without Mids) this is where you've gone. Not using Purple IO's pretty much makes this the case anyway.
I'd probably try to come up with 2 or 3 slots to be able to enhance and run Tough for its S/L resistance. Best candidate I'd likely try to grab one from each Toggle and add 3 slots to Tough.
Doomguide
I'm looking to respec an old Spines/SR Scrapper, and get it to the Incarnate Soft Cap (with the help of Barrier's full duration +5% def) and would be interested in any feedback anyone has (doubly so since I've not planned a build for an Incarnate yet).
The primary goal was to soft cap, and then get a good amount of recharge (~perma hasten seemed a good spot). I also wanted to keep the cost reasonable, so I didn't bother with Purples or PVP IOs (besides the one +Def IO). Thoughts?
Hero Plan by Mids' Hero Designer 1.954
http://www.cohplanner.com/
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Level 50 Magic Scrapper
Primary Power Set: Spines
Secondary Power Set: Super Reflexes
Power Pool: Speed
Power Pool: Fighting
Power Pool: Leaping
Power Pool: Leadership
Ancillary Pool: Leviathan Mastery
Hero Profile:
Level 1: Lunge -- Mako-Acc/Dmg(A), Mako-Dmg/EndRdx(3), Mako-Dmg/Rchg(3), Mako-Acc/EndRdx/Rchg(5), Mako-Acc/Dmg/EndRdx/Rchg(5), Mako-Dam%(7)
Level 1: Focused Fighting -- LkGmblr-Rchg+(A), LkGmblr-Def(7), LkGmblr-Def/EndRdx(9), LkGmblr-Def/EndRdx/Rchg(9)
Level 2: Spine Burst -- ScrappersS-Acc/Dmg(A), ScrappersS-Dmg/Rchg(11), ScrappersS-Acc/Dmg/Rchg(11), ScrappersS-Dmg/EndRdx/Rchg(13), ScrappersS-Acc/Dmg/EndRdx/Rchg(13), ScrappersS-Rchg/+Crit(15)
Level 4: Focused Senses -- LkGmblr-Rchg+(A), LkGmblr-Def(19), LkGmblr-Def/EndRdx(19), LkGmblr-Def/EndRdx/Rchg(21)
Level 6: Hasten -- RechRdx-I(A), RechRdx-I(21)
Level 8: Impale -- Dev'n-Acc/Dmg(A), Dev'n-Dmg/EndRdx(23), Dev'n-Dmg/Rchg(23), Dev'n-Acc/Dmg/Rchg(25), Dev'n-Acc/Dmg/EndRdx/Rchg(25), Dev'n-Hold%(48)
Level 10: Practiced Brawler -- EndRdx-I(A)
Level 12: Boxing -- Empty(A)
Level 14: Agile -- DefBuff-I(A), DefBuff-I(27), DefBuff-I(27), Ksmt-ToHit+(48)
Level 16: Dodge -- DefBuff-I(A), DefBuff-I(29), DefBuff-I(29)
Level 18: Quills -- Oblit-Dmg(A), Oblit-Acc/Rchg(31), Oblit-Dmg/Rchg(31), Oblit-Acc/Dmg/Rchg(31), Oblit-Acc/Dmg/EndRdx/Rchg(33), Oblit-%Dam(33)
Level 20: Quickness -- Run-I(A)
Level 22: Tough -- S'fstPrt-ResDam/Def+(A), GA-3defTpProc(33)
Level 24: Weave -- LkGmblr-Rchg+(A), LkGmblr-Def(34), LkGmblr-Def/EndRdx(34), LkGmblr-Def/EndRdx/Rchg(34)
Level 26: Ripper -- Oblit-Acc/Dmg/EndRdx/Rchg(A), Oblit-Dmg(36), Oblit-Acc/Rchg(36), Oblit-Dmg/Rchg(36), Oblit-Acc/Dmg/Rchg(37)
Level 28: Lucky -- DefBuff-I(A), DefBuff-I(37), DefBuff-I(37)
Level 30: Combat Jumping -- DefBuff-I(A), DefBuff-I(39)
Level 32: Throw Spines -- Det'tn-Acc/Dmg(A), Det'tn-Dmg/EndRdx(39), Det'tn-Dmg/Rchg(39), Det'tn-Dmg/Rng(40), Det'tn-Acc/Dmg/EndRdx(40), Det'tn-Dmg/EndRdx/Rng(40)
Level 35: Evasion -- LkGmblr-Rchg+(A), LkGmblr-Def(42), LkGmblr-Def/EndRdx(42), LkGmblr-Def/EndRdx/Rchg(42)
Level 38: Maneuvers -- LkGmblr-Rchg+(A), LkGmblr-Def(43), LkGmblr-Def/EndRdx(43), LkGmblr-Def/EndRdx/Rchg(43)
Level 41: Build Up -- RechRdx-I(A), RechRdx-I(45)
Level 44: Water Spout -- Posi-Acc/Dmg(A), Posi-Dmg/EndRdx(45), Posi-Dmg/Rchg(45), Posi-Dmg/Rng(46), Posi-Acc/Dmg/EndRdx(46), RechRdx-I(46)
Level 47: Hibernate -- RechRdx-I(A), RechRdx-I(48)
Level 49: Summon Guardian -- ExRmnt-Acc/Dmg/Rchg(A), ExRmnt-Acc/Dmg(50), ExRmnt-Acc/Rchg(50), Dmg-I(50)
Level 50: Agility Core Paragon
Level 50: Reactive Radial Flawless Interface
Level 50: Ion Core Final Judgement
Level 50: Barrier Core Epiphany
Level 50: Cimeroran Core Superior Ally
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Level 2: Swift -- Empty(A)
Level 2: Health -- Numna-Regen/Rcvry+(A), Mrcl-Rcvry+(15)
Level 2: Hurdle -- Empty(A)
Level 2: Stamina -- EndMod-I(A), P'Shift-EndMod(17), P'Shift-End%(17)
Level 1: Brawl -- Empty(A)
Level 1: Critical Hit
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 4: Ninja Run
We've been saving Paragon City for eight and a half years. It's time to do it one more time.