Perhaps, if they are putting Makeb as 1.6 (big if at the moment), they didn't want the PvP testing to be overshadowed by "omg planet
"? This way they can have PvP'ers levelling on the new map (no character copies this time, again) and discussing their issues without having to compete with "look at this shiny rock I found, I hit this quest NPC with it".
PvP's last map came out in April? It came with Denova, at any rate. They need some "me" time.
Not that story players don't need "me" time, of course, but there's usually a lot more yelling of "how can you like story? GAWD" involved and it requires less balancing issues.