The Good: Its a step in the right direction, allowing people to roam through an open world with almost full freedom. The new pokémon feel fresh, and even when they have ties to old pokémon, their connections are unexpected and interesting. The three storylines are not net new--it's still your basic gym, team rocket, legendary pokemon paths--but they are expanded and enriched with great character and small variations that avoid making it too boring.
The Bad: I mean, you have seen the footage by now. Its definitely broken in many bad, sad ways. This could have been a 4.5/5 if not for just how unpolished the final product is. Additionally, as a completionist it's still difficult to accept no full national dex.
The Verdict: While it's clunky and ugly at times, the brilliance of the ideas is still able to rescue this game from being a total wash. If you've been a fan of this franchise for a while, you're going to find a lot of the changes to be cause for optimism for the franchise's future.