We have no idea what the next Big Thing will be. Anything regarding such is 100.0% rear-end pulled speculation, so please don't try to spread misinformation. :-|
As far as MNK goes, I agree that it had too long a day in the sun and that the devs are not likely to allow it to become dominant again. There is no reason why it needs to be as far below others in general though and H2H WS could indeed stand a buff. Personally, I get the feeling that the main "con" for the devs on this matter is that any direct buff to WS will also affect PUP. SE has a proven track record of not knowing how they should handle pet jobs, and I would be surprised if the devs were not worried enough about PUP's combined master+pet damage potential that MNK suffering is just collateral damage.