Without a build its hard to say anything but lets see. First there is no useless power in SR except Elude. Elude is also useful if you don't have soft cap defenses (%45 at ranged, melee and AoE but a good number would be at least %46.5)
On Kat side remove SoW and get GC its better power that you can chain you attacks with just hasten. Top attack chain of katana is GD-GC-SD-GC but for AoE you can go for LD-FS-GD-FS this one needs a little bit recharge bonus to make but if you plan to IO your build anyway you will have enough recharge to do this with hasten. Ofcourse my second suggestion is getting flashing steel for AoE attack chain.
I am playing with no medicine pool with inspiration its managable but I suggest to keep medicine pool for aid self. I use leadership frequently for tactics, assault and manuvre but as a defence/endurance ration combat jump is better than maneuvre (also it will still pass soft cap of defence the full sloted difference is like 0.8 or so) tactics is not that necessary since all of katana attacks you will take does -def and you can use build up for IO slot.
You didn't wrote about your epic pool I am using body mastery with conserve power and physical perfection but I guess you can get any depending on your play style.
For sloting;
1) hecatomb set on Gamblers cut up to 5 enchantment (leave acc/rech one out you don't need it) + achilles heels -res proc. There is two reason for this gamblers cut hit twice although I don't have any solid evidence each tick checks proc seperatly (I saw numbers differ greatly) second reason is this power will be used twice in your attack chain so having it hit with both hecatombs negative damage proc and achilles heels -res proc increase your DPS.
2) Armageddon set in golden dragonfly up to five ench (don't put proc one in this unlike gamblers cut you need extra recharge on this power and you want this one hit so accuracy is a good addition)+fury of gladiator's -res proc (this one is optional, I don't have this since its very expensive ench but it should be make a difference in your DPS and any build on these forums that is not on a budget will have this)
3) 5 luck of the gamblers + global recharge, put these in 3 SR auto slots, weave and combat jumping.
4) Red fortune in toggle SR sets up to 5 ench on each defense ones prioritised. You can put 6 too if your ranged defense is too low.
5) +recory, +regeneration enchantments in heath, aid self, aid other and performance shifter +end proc in stamina (and in physical perfection if you take it)
6) steadfast +%3 res/def enchantment in tough.
7) Gaussian syncronised targetting control: +build up in either tactics, build up or focused accuracy (depends on which one you take if you put it in a toggle one it checks procin every 10 sec but it may use it while not in combat if toggle is on)
Other than these nothing else comes to my my mind at the moment.
You need to aim for getting your defence to softcap (%45 for melee, AoE and ranged) and try to get at least %100-105 (with quickness and the enchntment's i wrote you should have %92.5) global recharge without hasten it makes hasten perma and with hasten being perma you can run both attack chains uninterrupted, perma practice brawler (which is one of most important power since it gives mez protection)
For incarnates I suggest getting reactive radial flawless interface in addition to yours, others are depends on your play style.
So, I currently have a Kat/SR scrap, I wish I could post my current build but I don't use a PC or run boot camp. I love my toon he hits hard and barely gets hit. But my main concern is seeing what other builds or what IO sets I should be using. I have SoW, LD, SD, GD and of course BU, Kat side. SR wise I have FF, FS, agile, dodge, PB and quickness. the power pools are simple, hasten, leadership, fighting and then medicine...figured that would be helpful but, I kinda want to get sj and keep ss drop medicine. Anyway if any of you scrapper build kings wouldn't mind posting up some builds that would be great!! Also, I have no influence issues and most of my stuff has purple IO sets anyway.
Oh almost forgot! Incarnate wise, i have the Musculature Core paragon, Diamagnetic Core flawless interface, Barrier Core Epiphany, Almost finished with the Warwork Core superior ally (i have the incarnate shift), and almost done with the Ion Radial Final Judgement.
Thanks again to everyone who decides to help!