I wouldn't be against any buffs to Sion, but I don't think he needs anything major.
I play him top lane and as a jungler and I do just fine.
You don't need to charge your Q for the full duration to get the knock-up.
You don't always need to use your ult at max range.
Using your ult at point blank, triggering your shield, and landing your Q then detonating your shield is an amazing combo.
Don't try to ult that Leblanc or Zed, they'll blink out of the way.
I wouldn't recommend playing Sion on a team without other hard CC. Sion's specialty is to soak damage and stun-lock. If you have somebody like Lux, Thresh, anybody else that can lock down a target, you're good to go.
Maxing his W is how I always do it. Once you get it to level three with some health items, its not hard to detonate it for the damage. Pay attention to your opponents cooldowns. If they have a dash, wait for them to blow it, then use their CC. Worst Case scenario (as long as you don't miss) they burn flash for your ult. And that's a good trade.
Honestly, playing Sion comes down to common sense. Be aware of what your opponents can do to dodge your skills, be aware of what your allies can do to help you land your skills or work theirs off of your CC.
I see so many people complaining about how useless Sion is, but I don't feel as though they really play him. He's doesn't do everything, but what he does do, he does it very well.
And having a 300 ping isn't going to affect your gameplay? You're nuts.