It is a new reboot and the BW series won't have anything to do with the past series before it.
Except for where it's still very much in continuity with the umpty-dump sagas that occurred before it, meaning it's not actually a reboot in the factual definition of the word, which in turn means this whole thread is basically people arguing semantics in the least intelligent fashion possible.
Kids, listen up: as fiction goes, a reboot is generally defined as actually throwing out everything that happened previously and completely starting anew. Not "starting anew but everything that once happened still happened", actually completely starting over. Comic books do it all the time. Every other week, it seems.
Batman Begins is a reboot: it completely ignores the four previous Batman films and starts over completely.
Fullmetal Alchemist: Brotherhood is a reboot where the anime is concerned: it completely ignores the first anime and starts anew, following the manga more or less verbatum. Countless other anime and manga series have done reboots into new and separate continuities, which, again, involves completely ignoring any previous events and stories and starting completely over from scratch. Best Wishes is not doing that at all. Everything that's happened in the anime in the last 13 years still happened, is still valid, is still canon, is still in continuity.
Best Wishes is
not a reboot, at least not per the factual definition. You can call it a reboot in your respective minds if you want, but that's semantics at best and just plain inaccurate otherwise.
Best Wishes is nothing more and nothing less than what Johto, Hoenn and Sinnoh were: Ash starting a new quest in a new region. It's no more of a "reboot" than Hoenn or Sinnoh were. It's somewhat more of a "reboot" than Johto was, since he took both members of his supporting cast and all of his Pokémon with him, but still, the point remains none of those are reboots - that's starting a new story arc. Nothing more, nothing less.
There. I just saved the rest of you schmuckdog millionaires from any further mindless arguing and pissing matches. Go outside or read a book or something.