As someone who is new to competitive play and has no experience in playing either with or against BP teams, let me ask one question that to me seems like the most fundamental one for the discussion at hand. Do we want BP in the metagame or not?
Of course one could simply play counters, but if only 5% of players use BP and you win those 5% of your matchups with your counter (assuming there is one hard counter, that is) you'll probably lose most of the other 95% since it's basically a 5v6 from the jump.
Now, what interests me in competitive Pokémon are things like: Mind games, matchups (that includes improving individual matchups by running unconventionals sets etc) and predictions, all of which are a constantly changing process in individual games as well as in the metagame itself. It's what makes the game interesting, at least to me. Like I said, I'm fairly new, so correct me if y'all feel different.
From what I gathered, BP tries to basically ignore ALL of that. It doesn't particularly care about team or individual matchups, the opposing player or the metagame environment. It tries to execute the exact same strategy the exact same way using the exact same team every game, deviating from it only if it is absolutely necessary. In my personal opinion, such a strategy is non-vital to the game and I'd have no problems with it being removed completely.
As I said, I'm neither a butthurt player who keeps losing against BP nor am I a player who uses it himself, I'm just trying to wrap my head around what it does or tries to do in a given game. From what I gathered, BP tries to do the exact opposite of what makes competitive Pokémon interesting (beating individual matchups, predicting the opponent, tweaking teams). If a more seasoned BP player disagrees, please correct me here since I'm completely going from what I read itt. I think it's a really interesting strategy and concept, but other than that, I don't see the point of it being used in competitive play.
Now, most of the arguments in this thread I read so far revolved around the question of what combination of moves or mons or how many of them should be banned, but I think the question that needs to be solved first is whether BP is "wanted" in the metagame.
If yes, a slight nerf should do the trick, if even that. If not, limiting BP users to 2 or 3 should suffice. It keeps QuickPassing alive, allows for BP to serve as a pseudo-VoltTurn while still destroying full BP teams.
I'd love for pro/con-BP players to make their points, since most of what I read in here are discussions about whether or not it is possible to counter BP, but that's beside the point to me.
TL;DR:
Baton Pass players, why should full BP teams be playable? Where's the fun in using them?
Non-BP players/advocates of a BP ban/nerf: Why should BP not be playable? Where's the fun in playing against them/is there fun in outplaying/countering them?