It seems like a way to make low-level grinding (perhaps with that $35 Pokémon Go Plus dongle) pay off visibly and as the post title puts it, increase the odds of catching rare Pokémon. The only problem? At least judging by the responses, players are really looking for ways to improve other parts of the game, like tracking monsters, or battling and training in gyms. Niantic previously said it would "rebalance" training battles, but that is apparently also still in the works.
Update: Apparently Niantic heard us because it's also revealed the training rebalancing is coming soon. Now, when players train at gyms controlled by the team they're on they will bring 6 of their Pokémon, just like a battle against other teams, instead of only being able to use one. Also, the CP (combat power) of the Pokémon in the gym will be adjusted to match the level of the player.
Basically, this will make it possible for lower level players to train Pokémon and get them into gyms at all. Under the current system, casual players stuck at lower levels or are just starting off can't do much to get a Pokémon into a friendly gym or snag the free bonus coins that are available as a result. It doesn't make it any easier to take the fight to other teams, but now even if you're at a lower level than other players in your area, you will have a reason to actually stop at gyms again.
Unlike the capture bonus change, this has been met with a positive response, because it responds to a concern players have had since launch. The only problem? We still don't know when the update will arrive.