I agree that another Malzahar skin would be great! How about this one:
Blade Master Malzahar - It would be amazing and a nice nod to AD Malzahar players. It would be the first follow-up skin in the Blade series. So far, we just have Blade Queen Lissandra:
http://ddragon.leagueoflegends.com/cdn/img/champion/splash/Lissandra_2.jpg
Here is a quick (MS Paint lol) sketch I made for the concept:
http://i.imgur.com/GZxyi6v.png
Q: Two green ethereal blades appear at the edges of the cast area and then slash towards the center after the delay period
W: A portal opens in the ground, exposing a metal spike trap (the spikes could be either stationary in the trap or animated to perform a repeated mechanical thrust/stab motion upwards like the example gif below)
http://vignette3.wikia.nocookie.net/siegefall/images/4/40/Trap01_01_sp.gif/revision/latest?cb=20150619200622?noredirect
E: A cluster of green ethereal needles/daggers circles the victim's head, repeatedly stabbing during the spell duration
R: Malzahar emits a constant stream of small metallic blades/shards surrounded by cracks of green lightning. The blades are seen piercing the victim in many places (think Kalista's Rend), essentially immobilizing them via "stapling" as a rather grisly variety of impalement.
Voidling Frenzy: The Voidling's green eyes glow brightly and a sound is played like metal being honed.
With this skin, I think that it would be somewhat important to emphasize the Voidlings a bit. As I mentioned earlier, this would in part be a nod towards AD Malzahar, and most of AD Malzahar's damage comes from his Voidlings. Therefore, the Voidlings should look intimidating, with gleaming sickle bladed limbs, sharpened to a razor's edge.