he said that with maximum battle rank the player is awarded with additional health
Think you may have misheard, because this is definitely not a thing.
Overall though, I'd say the balance discussions/loadout guides/weapon reviews (which amounts to a lot of the content) is outdated. The live gameplay/montages/tips and tricks are mostly relevant still, and the Thoughts on Better Gaming series is pretty evergreen, but it's also not always with PlanetSide 2 content in the background.