Are you guys sure WG will do this? They may be testing the waters, and if they do nerf a premium ship that will set a bad precedent. The people who buy premiums might lose trust in WG too. After all, what guarantee do players have that the shiny new premium they bought won't be utter garbage once a patch hits? Sure WG probably wouldn't make a premium ship useless, but the possibility exists and if they do this players might be less likely to buy any new premiums.
Even if they could balance all of the premium ships in the game amazingly I wouldn't agree with it. Simply based on the fact that if they change one premium ship, they very well could change another. They could change a ship in ways that the people who play it would despise at a moments notice even if they had balanced things well until that point. The fact that a precedent would exist at all if they did this wouldn't be good.
Besides, when did 'a healthy game' ever shape a company's decisions? Sure a developer might make such a choice, but the people up-top sitting in the boardroom? Money and pleasing the shareholders is what matters at the end of the day. If WG wanted to balance premium ships they should have done so from the beginning. Instead they've let these ships remain unchanged for years. If that changed now there would be outrage and the cash cow that are whales might stop buying as many premiums as they used to, which would lose the company money. Even if in the long run such a thing would be good for the game that's not what would make them money right at this moment.