Yes, some pages ago, I think Great Khan and me were talking about a Space Pirate invasion like Terraria already has. And I said something like that I always feel the Space ivasion with the right music is like the Metroid ones for me. Then you said you have planed one already.Although I haven't really written it down, I have been thinking about including content from Hunters. At some point there may be a large update centered around multiplayer compatibility and/or bugfixes, and that update may include Prime Hunters content as a way of "celebrating" it. The Hunters content may even compliment Terraria's already included PvP stuff (like Capture the Gem).
On another note, I believe I've mentioned before that a "Space Pirate invasion" mini update is also planned, which will introduce more types of Space Pirates.
(Currently, there's only gonna be like 1 type of pirate for first release.)
Is nice the release will have one pirate.
You are right, the Prime Hunters go very well with the PvP. Never tried it, I am more relaxed if am playing multi, and rarely do. Prefer to take my time with things... if you could see my current playthrough... I am not in harmode yet! I am building some things I will need like an Old Army arena or the stone bridge in Unddrworld for farming the WoF and Souls.