Shika: I love that abstract. Very nice colours and it's good choice of C4D. Though, it's looking way too empty towards the left, in my opinion. Maybe the SOTW text could go above the line of squares, aligned to the right? Or completely replace the current text, and make it just say SOTW instead. I'm not sure. And I don't think it needs a border. It looks pretty darn good enough as it is ^^
Loki: I like it loads :D It's bright and colourful, it has a wide variety of effects from those box-ish things, to the spatters, and yet it doesn't look cluttered. And those green/red lines add great flow. The shadows to some of the shapes add depth, too. I also like those dotty stuff on the render, so it makes it look less empty. Ah, and it took me a while to realise the border. It's nice and rainbowy.
Ishida:
Altair/Assassin's Creed banner: Yup, that's definitely monotone D: The little light textures add a nice effect, though the on his shoulder to the front looks slightly distracting. I like the use of effect C4Ds, though. I'm with Perfectionist in saying that the render blends in too well with the background. Tone it down a bit, especially on his face/head and his hand. And try to add flow. Put effects in that help to emphasise the diagonal flow of the banner, which goes like: /
Lelouch banner: Yes, it is looking quite bright. Though I don't really mind. It looks over sharpened, though, especially the light effects. I don't really like the giant splodge on his shoulder and the text could be better. Add stuff to the background, too, maybe scan lines, or spatters or something, just so it doesn't look too empty there. Though I like the colours of the render itself.
Perfectionist: That's a nice attempt. The render looks adorable xD Though it's looking a bit too blurry, maybe go: new layer, image > apply image, then filter > sharpen > sharpen. Add some lighter spatters away from the render as well, just to spread the colour a bit. And maybe shift around the clipping mask, like tilt it diagonally, so that it covers more space in the banner.
---
Hooray for my graphics slump :\ I need to work on the colours, but I can't be bothered to do that right now, eheh.