Eh, most of the questions in the OP do not reflect what the title said, but oh well ...
Anyways, I do not want to go all the way as to say that Zero-G is broke, but it certainly has controlled significant parts of the meta in BB-10.
On Synchromes in BB-10:
For example, Flash is barely viable anymore considering all of those Synchrome Attackers that can do on-par or slightly worse. In Defense, Synchromes are your best option. Considering that Flash can handle Duo, then Synchromes definitely can. Stamina is one of the only types still viable that has not been taken over by Zero-G. Duo and Phantom are still your best options. As for Balance, I know there are Synchrome combos out there, but they have not taken over the Balance type. Duo ___ 230MB is still useful, and I personally love the combo. Synchrome Spin Stealers have more or less taken over the type. Meteo is outclassed, and IMO L Drago Destroy/Guardian only has niche uses. Dragooon is the way to go now. It is heavy, left spin, and is more or less the Jack of All Trades. It has uses in Attack, Defense, Balance, and Spin Stealers.
On new Tracks and Bottoms released in Zero-G (in BB-10):
Where do I start. I guess from the beginning. W145 was originally put off since some thought it would equal DF145, i.e. stink. Then testing was done. It is now amazing for stamina, putting AD145 in the dust. Some even say it almost has outclassed AD145. CF has not seen any mainstream uses since it was released. Orojya is only OK for stamina, being outclassed by Duo/Phantom. Phoenic is great for attack, but don't know too much about it. E230 however, is a "game-changer". I mean, BD145's disk+230's height=crazy defense. Even this part has not taken up the meta game. High attackers (mostly Synchrome setups, Flash is not good on high heights) can handle E230. As for BD145, attackers that can make contact with mostly the MW (like 160) can beat it. So, again, E230 has not taken over the whole Defense meta. On to 160. It does have OK stamina, but W145 outclasses it. I think it is best for attackers, specifically Flash. Inguilt said he personally likes Flash+160. As for SB, nothing really good about it from what I have seen. Now for LW160. Not exactly sure where it stands in the meta. I mean, I personally have never heard of left spin stamina, they all end up being a spin stealer. Its height makes it vulnerable, anything low. As for BSF, I think KainHighwind knows it best. From what I have seen, he says that it works similarly to MB. It can tilt to "scoop up" opponents, or force smash them. It provides decent aggression and stamina. SA165, the flower pot of doom. It provides great LAD, and decent stamina. Otherwise I am not sure what it is good for. But its LAD puts it above all else when paired with Revizer and Dragooon. Now for SR200. I am not really sure what is is good for, except that KainHighwind and Inguilt have been doing exciting things with it. It mostly from what I've seen is make TB shine in terms of stamina. BWD. The next bottom of the D series. It seems like it is good for stamina, and can replace EWD in Revizer Dragooon SA165 EWD. On to F230. I am not sure what its uses are in the BB-10 meta. As for TB, it has stamina. It seems great IMO, but it works best with SR200. SP230, the fixed E230 with spikes. In anyway, E230 does better. Spikes do not help, hah. Now, GF. GF. GF. Just plain amazing. It is like a flattened D. Just so fast. Remember Meteo L Drago CH120XF? GF replaces XF, and does so well. It is hard to explain, other than that it is great. Check out Meow!'s video comparing it to other versions in the Flat family.
So over, Tracks and Bottoms released in Zero-G were pretty influential on the meta.
On General Zero-G in Zero-G Stadiums :
No where near enough testing. I myself need to test more, but yeah. Anyways, Synchromes are pretty influential, just as in BB-10. But the attack using swaying aspect in general was actually pretty flawed. With right vs left spin, if right is using Sway Attack, it will usually lose, unless left spin is using an aggro tip. CF and GCF are not fast enough to handle left spin. The part that can do this though is GF. I don't have it, but ShinobuXD's video helped a lot. The thing is crazy fast.
But yeah, definitely more testing is needed.
But overall, Zero-G had a huge impact on the meta, and while it is not broke it has somewhat taken over the tier list.
Hope this all made sense.
/rant
4/29/12: The Spring Sortie (BB-10)
7/22/12: The Triple Threat (MFB+Plastics+HMS formats)
9/23/12: Autumn's Assault (Zero G)
October 2012: October Achtung (Zero G) (placed second)
12/15/12: Holiday Havoc! (Zero-G)
2/24/13: Paper vs. Plastic (Zero-G+Plastic Formats)
4/21/13: BR Maryland Qualifier (Zero-G)
5/26/12: BeyDays 2013! (BB-10) (placed first)
7/14/13: Heated Metal Plastic-y Madness! (HMS + Plastics) (placed third in HMS)
7/20/13: The Bey Brawl! (BB-10)
9/28/13 "OK, alright, mirai~!" (BB-10) (placed second)
12/15/13 No Limit Holdem'! (Zero-G, Limited)
1/19/14 Happy Gnu Year! (Zero-G)
2/23/14 Better Late Than Never! (Limited, Plastics, which I got 3rd in)
3/29/14 GBT2 North Carolina Qualfier (Limited, got 4th)
3/30/14 GBT2 Maryland Qualifier (Limited)
6/8/14 A Prehistoric Venture (Limited, HMS, placed first in HMS)
6/21/14 A Timely Farewell (Standard, Tag-Team (not official format), Zero-G, placed first in tag-team and third in Zero-G)