This is a stupid debate. I've come down hard on spoilers in general, but sometimes it's just stupid. Episode title? Not a spoiler. Discussing centricity? Not a spoiler. If you go into the next episode knowing that the title is The Last Recruit, and thinking it is everyone-centric, there is no way it will diminish your possible enjoyment of the episode.
The title could be referring to anything. It could be referring to MIB recruiting his last ally, which is certainly what they want it to sound like, or it could be something in reference to the X timeline, or it could be both. Either way we don't know who is being recruited. No spoiler.
The centricity can't spoiler anything either. It's either about a character, or it's about multiple characters, or it is not about any character off the island. None of these could possibly make someone enjoy the episode less.