Mordekaiser needs an update soon!
I've only been playing League for about a year now, and I've played just about every champ available. My favorite, Mordekaiser, has stuck with me for most of my time playing. With all of these new hyper-mobile champs being released, Mordekaiser is getting harder and harder to play. I think he should get his update ASAP (Tristana is getting the next one, but I think that she's MUCH more viable than Mordekaiser). I LOVE his theme! The whole evil spirit in a giant suit of armor with a mace is just awesome. As much as I love him, he doesn't make much sense gameplay-wise. He's a Melee Mage, which usually doesn't work out so well (unless you're Fizz, Akali, or Katarina, all who have a lot of mobility). He has to get close to hurt anyone because of his lack of range. He has a ~700 range poke, but that's about it. If he wants to combo, he has to wait for his opponents to get close to him, because he can't chase without any mobility or CC.
ANOTHER weird thing about Mordekaiser is that he looks like a TANK. He's made of metal, and he's giant (or at least supposed to be), but he's more of a Mage. If he did get a VU, he needs more of a glowy green look like the other SI champs. If you rework his kit into a mage styled kit, then get rid of the mace. It doesn't make sense for him to need it. If he becomes a fighter or tank (which I really would hate, I prefer a mage Mordekaiser), then let him keep his mace, but make it so he actually uses it with his skills. At the moment, Mordekaiser hardly uses his mace. The only time he really uses it is with his Q, and even that shoots out MAGICAL maces for some reason. Either a fighter or a mage, not both.
Another thing I would like is that you keep his Passive and Ultimate. They are very unique to him, and are core to his identity. The rest of it can be changed, but keep those. He needs a skill that drains the lifeforce of the enemies, and slowly brings them to their fate of being your sp00ky slave. I know his Passive and Ultimate are powerful, but the rest of his kit isn't as strong. Right now, he's balanced out (or underpowered) because of his lack of mobility, no CC whatsoever, nothing to increase his movement speed, melee, and health costs without a basic sustain (ultimate isn't a reliable source of sustain).
TL;DR - Mordekaiser needs his update ASAP due to the mass amounts of mobility showing up in order to stay somewhat viable. He's long overdue, and needs some love; visual and gameplay.