I haven't spent too much time laddering with the team, but after a few hours these are my thoughts.
- HP Ice on Keldeo would definitely be quite nice and I think thats what I would go with, although if Terrakion goes down early somehow Gyarados can become a serious problem, so while I think Ice may be better, I wouldn't want to get rid of Electric until more people have expressed their findings.
- Rain teams; Now I know this was strongly taken into account when selecting the latter members of the team, Latias and Bronzong in particular being selected to check rain teams, and Latias for sun also. A ScarfToed can potentially 2HKO Bronzong after rocks, ~22% chance, so its unlikely but taking 44.51 - 52.52% on the switch in to stop say Gliscor eating the Hydro Pump severely cripples Zong. It also prevents it from dealing with Tornadus-T as well as it will only be able to take two Hurricanes before its KO'd, meaning thats two switches at best and our main Torn-T check is gone. Jirachi doesn't fare a whole lot better, but it does outlive Zong in this situation. I'm not saying we should switch Zong for Jirachi by any means, I just think that it isn't really working as well as we could have hoped.
I have found that once Zong is gone Rain teams become a serious problem, especially ones with both Torn-T and Breloom, which are becoming more common, because then Terrakion is no longer as safe a check to Tornadus. Latias can do alright sponging the weaker Scalds/Surfs, and doesn't even mind the burn all that much thanks to Recover, but it does get worn down quickly seeing as its basically it and Zong trying to take all the hits. I think something definitely needs to change in the team to better deal with Rain teams at the moment.
-EVs on Tyranitar; I strongly agree with what Penguin posted earlier in regards to changing Tyranitar's EVs. Granted we do lose a lot of special bulk, which can be very helpful, however the increases to speed and power have been well worth it in my experience, OHKOing Deoxys-D as it Taunts you is a great feeling :3. With the more defensive spread it can also come in on weaker Water attacks in the rain, but you really don't want to come in a Scald and risk the burn, as such I don't think that it would be too large a sacrifice to shift the EVs to a more offensive spread.
- Latias; From what I've found so far its that I keep wanting Psyshock on Latias, and I really am not using HP-Fire all that much. The main things HP-Fire is used for are the 4x weaks to Fire, and often those will be found under rain. Granted there are the situations where you can kill Toed and then get Sand up thanks to TTar, in these situations HP-Fire is really nice, however I find these few and far between. I have noticed that a well played Breloom can cause problems for the team. Psyshock would seriously mitigate this problem, without losing out too much on the things we'd use HP-Fire on. Granted you now really can't hit Steels, however I have found that Keldeo's Hydro Pump either in or out of rain after even just 1 Calm Mind seriously hurts them.
- Breloom; As I mentioned earlier a well played Breloom could be a problem. Lets say its a 252 Atk, 252 Spe Jolly LO TechniLoom with SD/Spore/Mach Punch/Bullet Seed it can seriously go to work on the team. Lets say it gets an SD up (assuming rocks are up), it can then OHKO Tyranitar, Gliscor (if it gets 3+ hits on Bullet Seed), 56% chance to OHKO Terrakion with Mach Punch, or guaranteed OHKO with 3+ Bullet Seed hits, however more likely to Mach Punch due to Terrakion being Scarfed. Bronzong would win out as it takes Breloom about 3 attacks to KO it after rocks, in which Bronzong could be firing off HP-Ices. Latias obviously wins, provided it has more than 27% health, although if its close to the 27% mark it'll potentially go down due to LO recoil, or it can attempt to LO Stall Breloom if it comes in with higher HP. Mach Punch maxs at about 55% on Keldeo, so as long as it has more than that it'll aptly deal with Breloom. Not entirely sure if changes should be made to deal with TechniLoom, however it should definitely be kept in mind as something that can cause problems.
Just a few of my first thoughts, I'd be interested to see if others have identified anything similar to that, alongside other possible areas for refinement.