The balance issues as I see them
- The Walker Gear can turn 180 degrees on a dime, where it should take a second (like it seemed to on the MGO3 reveal trailer). It isn't the biggest issue, but that would go a long way towards balancing it (that, or giving it a uniform turn speed like the turrets).
- Stealth Camo. It's more of an issue due to the in-game response to it: E.Locators. Being hard to see, but still being able to dash around with a shotgun or assault rifle, means that Infiltrators have an unfair advantage, until...
- E-Locator's enter the picture. You can carry a bunch. They mark targets who enter their zone. It changes the core game for the worst. Instead of worrying about OP Stealth Camo I can throw an E-Locator at most corners of frequented locations and know the exact position of someone in the enemy team, or that the area has no enemies. Instead of not seeing some players you see most of them for 90% of the match, and they see you. It kills any stealthy play. The game devolves into waiting for red silhouettes to be shootable.
Fixes for the E.Locator would be keeping people who have been marked by them marked for only a second when they leave the region, reducing the duration where they are active, and reducing the amount you can carry from 3/5 to 1/2, the latter number in each of the two pairs being the extra amount you can carry with the Ability that gives you more support ammo.