Taking Clarity is worth a downvote in itself.

Not taking Flash is also worth a downvote as well as the lack of Sightstone as a support.

Masteries are terrible and Ziggs requires Athene's Unholy Grail.

If you want to play him as a burst mage, play him mid. Don't waste your team's time with this.

I've been playing Ziggs support as one of my main options since the last buff to Spellthieve's Edge. He really is strong. Some different opinions though:

- If you don't buy a Sightstone, then you are no support, but a troll on bot lane. You can get away with a lot of playstyles, but with the current blue Sightstone having 3 ward instead of 2, there is just no excuse not to have one. You can delay it until after Frostfang, but that's stretching it.

- I personally find Flash/Exhaust much better. Without it you are a lane bully. With it you are a lane bully and will likely have first blood. To make up for the missing mana I start 3+1 or 2+2 Cookies/Mana Potions, depending on enemy champions.

- I run hybrid pen, instead of magic pen. You want to land q+auto attacks early on.

- A lot of your guide is written like you play Ziggs as a troll who snatches minions when he can, and who stays in lane when you adc goes back. That's ********. Clear the wave, go back, be back to the lane with your adc, you're supposed to support him.

- On items. Zhonyas/Lich Bane should be optional. Ziggs is on the back line of a team engagement anyway, and if the enemies are so desperate that they start focussing you, you have done everything right. I would only build Seeker's Armguards if they have some mad snowballing chain killing ad assassin like Yasuo or Kha'Zix or Talon, but when those guys are 7/0 there's little you can do anyway. Lich Bane - no. You are behind on items and you don't want to be near the enemy. Build Liandry's as last item instead for percentage damage. And only add Zhonyas if you're in 55min, have 5k on hold and sell your Sightstone.

- I prefer Homeguard, so you can call back more often for Sightstone charges and mana.

- Core items should be: Frostfang, Sightstone, Sorc boots, Chalice.

http://pluc.me/lol_s4_masteries/#Ma5Gv5jsSAvA
This would be an example for a more optimal Mastery Tree imo.

If you don't buy Sightstone you can go mid aswell because helping your team is mandatory and vision is mandatory. Affording money in single Stealth Wards won't be worth after a bit amount of time in comparions to running Sightstone.

I don't run flash because I'm aggressive and like to secure kills with exhaust.
Invalid argument. You can play agressive with Flash aswell and even better. I think it's only Shaco jungle that might not Flash or Ghost but everyone else should do it.

It is good, however, flashing for a kill. That's always fun. And it pretty much makes you unkillable if your flash is up. Also it's great for when your 1v1 someone to flash behind them, making them miss an Ability and giving you the advantage.
Use these arguments as you essential reasonings.

Yeah I've used the offensive tree and I just find that the extra damage doesn't make up for the CDR, movement speed, gold income, and sustain the Utility tree gives you

The sightstone I didn't put as my core because I play very aggressive and pretty much just buy as many potions and AP as possible whenever I back. Sometimes I buy wards but by the end of the game normally that slot is taken up by a high damage doing item for me. Late game he is still a burst mage.

I don't run flash because I'm aggressive and like to secure kills with exhaust. It changes the flow of the game in your favor if used properly. Also, with the talisman, Ziggs now has 2 escapes so I don't think it's that necessary to have flash with his range if you remember to play safe. If you just don't have bad placement then you don't need it. It is good, however, flashing for a kill. That's always fun. And it pretty much makes you unkillable if your flash is up. Also it's great for when your 1v1 someone to flash behind them, making them miss an Ability and giving you the advantage. So yeah, it's very useful, that's why I put it as an option, but just not as necessary as it is for other characters.

But anyway thanks for the advice! I really appreciate it!!!!

Flash and Sightstone as a core item are essential imo. Instead of focusing that much on th Utility Mastery Tree you should consider spending more points in the Offense Mastery Tree.
Are and Clarity, be aware of critique.