..Wow... the giant reply I had typed.. Oi.. gone.. eaten because it loggged me out.. Okay, I'll do my best to start over and hopefully remember everything I had wanted to say.
So, anyway Dechs, it's me Nikku and you asked me to come check this out and I have and wow, I am impressed. Nowadays with most guides being builds and: "Pick this, this and call it a day." I must say, that your guide is a much welcome change from things I've seen. I also heavily enjoy it for the simple fact that, it's yeah, exactly the mindset I have when I'm on Nikku.
A LOT of the power choices and reasoning was the exact same as my own and why I went those choices, though I admit I wish I had noticed the greatness that was Gravitic Emanation. But hey, you win some and you lose some. Hahaha. And I cannot help but to smile seeing that you mention the positives about taking Stygian Return. Many people seem so against it, but I like not having to really worry about carrying awakens and there are many times I've just hit self-destruct and Stygian Return to get back some endurance or to just cause some damage because I could. (Long AV fights come to mind that just seemed to be taking forever with no new bodies to come say hi. Sigh.)
But, as you also mentioned, a lot of the choices you make in the warshade's life will be to your playstyle and personal enjoyment. For example, for early powers, I went with Gravimetric Snare and Gravity Shield. With a hold IO in Gravimetric Snare and in Shadow Bolt, I can fling around a quick few spam like attacks to try and lock down a few or help Controllers / Dominators lock down some hard targets and when the LGTF was bugged well, any sort of hold help was appreciated. Plus, I think with only one-slotted, in each, it does more then my Acc/Dam HOs did. And hey, despite all the recovery options, I still run stamina. Hahaha. Which I know my friends just kinda look at me funny for doing. Guess I just hate running out of endurance.
But really, Memphis Bill beat me to my big suggestion in a lot of handy IOs such as the Winter's Gift which I am very fond of. The only other one that comes to me off the top of my head and I find worth mentioning is the Stealth IO. Toss it in sprint and not only do you get full stealth as soon as Shadow Cloak opens up, I find it very easy to afford nowadays with Hero/Villain merits and it would save you the choice of a power pick, unless you wanted super speed to go along with your teleport, fly in Nova. Me? I'm content with ninja run, teleport and that nova flight.
The biggest piece of advice I can give that may help contribute or mention is that I know quite a few players who are terrified of binds / macros etc. I really don't use a single one of them, but I hated trying to arrange the powerbar and find a set-up I was comfortable with Nova and Dwarf powers being unclickable or vice versa when I'm in another form. I use the default HUD, but in the center between my Chat Bar and my Powers Tray I create a custom tray to fit snugly between those. I forgot the exact shape you can pick from, but one of them fits --exactly-- all your Nova, Black Dwarf powers including taunt and teleport. Put your form to the side, click and you have the perfect shape-shift power tray with no confusion or mess. So to those who feel apprehensive about giving Kheldians a try for fear of mastering macros / binds. You don't. Trust me.
Anyway, as I mentioned before, I wish I had C&Ped my original message before posting, but, what can you do and hopefully I remembered everything I wanted to say, but this was probably more then you expected, but since you asked, I wanted to make sure it was worth the read. Great job on the guide though, you hit the hammer on the nail and this should guide many a new & old players well.