Important Change for Dual Blades, Cannoneers, Merced...

Link skills, for one thing.

That answer needs elaboration.
Why would Nexon want to prevent people from making characters for linked skills?

Trying to counteract the bandwagon, forcing new players to try one of the older classes first?

New players are likely to be unaware of the nuances of the game and be immune to bandwagons.
Not that I see why Nexon would care if people bandwagon. If they did, they wouldn't make new classes that are so absurdly unbalanced.