Yeah, he needed a Visual Update, and although his voice was great, it just wasn't right, sadly. It was sad to see it go, but it was kind of necessary.
What WASN'T necessary, was the removal of everything that made him Sion. Especially his ult.
I don't mind the Q going. It was a dated ability, anyway, and point and click abilities that are that strong (when built AP, at least) are generally frowned upon by Riot. That's why they changed Zilean's Q.
The changes they made to his W weren't too bad, but removing the AP Ratio for the shield and heavily nerfing the AP Ratio for the damage was pointless. It was basically them saying "We don't want you to play this way", which is a thing that Riot has said they DON'T want to do to champions.
The total removal of his E was stupid. They really should have incorporated it into his new E, or passive, or ult, or ANYTHING. The fact that his new E scales poorly with AP only enforces the idea that Riot didn't want people playing AP Sion anymore.
The total removal of his ultimate is what absolutely destroys me. There will never be an ability that I miss more than Old Sion's ultimate. When you think about it, it actually went with his thematic, too. He was a crazy warrior who charged in recklessly, and that's pretty much what it was. You ulted, you went in, and you started auto attacking shit and being really hard to kill. It could have been changed, and changed a lot, and I'd be okay with it, but instead they just removed it, like almost everything else in his kit. That's why whenever I see a thread about Sion or something, I always throw a little hissy fit. I'll never stop being upset about the rework, and I think a lot of the people who played Old Sion (although there were few) feel the same as I do about him.
Sion needed to change. Not be removed from the game.
Also, I tend to learn towards the bad guys in stuff, too. My four favorite characters of all time are major villains. Cho'Gath, Destroyah (From Godzilla Vs. Destroyah), Sharptooth (From the first Land Before Time movie), and Giga Bowser (From Super Smash Brothers Melee).
Oh yeah. One more thing. I personally find the current Sion's voiceover to be a bit... over the top. "I'LL DROWN YOU IN YOUR OWN BLOOD!", "I... WILL BREAK YOU!", and then there's the choking he does after he dies. It's a little bit overdone, but that's just me.