Let me address some of your concerns.
1: The WGC launcher has always allowed you to install it where you want, just like any other APP, I have it currently on my D drive verses my C drive.
2: You can have an account on every server if you want launch through the WGC, if you click in the top left where it shows your screen name, down at the bottom it says "Add Account" there you can select what region.
in the case of the PTS you have to download the PTS client in addition to the actual client but WGC makes adding your credentials easy because they are saved in the launcher
3: if you use the WGC, there really is no point in having your old launcher so I don't see a problem here, however, up to the removal of support for not launching through WGC you can have it installed and still launch the client on it's own, so I am not sure how it "breaks the function of the classic launcher" I would need more information to know what you mean.
4: The news is shown on the front page of the WGC on the "World of Warships tab...
Also, I am unsure what the worry is about the WGC "collecting data" the WGC doesn't do so any different than the data that we collect while you play the game. Also both launchers collect the same data...
That being said, the data collected isn't malicious... I've been using the WGC since WELL before I have worked for WG and have never had issues with it.