With the recent ban of PokeAdvisor, many players are now unable to play the game in the way they desire to, which will eventually lead to a very large portion of hardcore/diehard players leaving the game entirely. This group of players are historically the ones who stay with a video game the longest, who provide free advertisement through their theorycrafting, and who have the most visible presence on large entertainment sites like Reddit and Facebook. They create the most engaging and entertaining content related to, but not affiliated with, the game itself; and this has been true for many games, to their extreme benefit.
I understand the intention of Pokemon Go is to get players to explore the world, and I am all for that. Encourage us to explore the world, but a lot of us can't go out at all hours of the day. I have explored a lot of my home town that I would never have seen or known about otherwise, all the while engaging in my style of min/maxing and theorycrafting.
For many players PokeAdvisor represented something that should have already been available through Niantic, but the reality is that third party persons will ALWAYS provide a service superior to the principle party in this area. The third party developers are passionate about what they're doing, they want to analyze the deepest data about their Pokemon and develop detailed rankings within their Pokemon and as such, know exactly what data they need and where they need it.
We request that you incorporate PokeAdvisor into the website you already have (or allow them to exist independent), it doesn't affect server function enough to notice (at most 4% of the overall game load) and allows a large number of your players to engage the game in the way they want to. We agree that most of these things shouldn't be readily visible in the game's api as it would overwhelm casual players (or even hardcore players who just don't care about stats much), but allowing us to access them doesn't give us any serious advantage. The greatest possible advantage is 21%, the average advantage is 13.7% for those who maximize their Pokemon's IV stats. In Gym battles this advantage is basically irrelevant, since teaming up with other Pokemon offers at minimum a 50% advantage when comparing equally leveled pokemon (even with less than ideal IV stats).
If your concern is multiple APIs, then allow ONE third party to develop something like PokeAdvisor (I recommend PokeAdvisor, because they did it best). It will only benefit your company long term.
In short, I make this one request to you, Niantic and John Hanke, let us play the game the way we want to play it. It doesn't affect anyone else negatively.