New playthrough for Blood and Wine. Wait until it is released or does it not have any influence on the base game?

So, as I don't want to start Blood and Wine with my 8 months old savegame I plan to do a completely new playthrough. Now the question is, should I wait until BaW is actually released or has it no real effects on the base game? Then I would start now and maybe reach the required level for BaW when it is released so I can start immediatly with the new area.

I mean, I read the feature list of BaW, but am too far out of the loop concerning Witcher 3 at the moment to really know how different the base game would be if I waited for BaW.

Any advice?