Well we don't really know how successful V2 was.
I doubt 2 of the 3 top ranking vissers were working on Earth at once, that host may have just been for the occassion. He is pretty high on the ladder, he can point and probably get any host he wants (which is why I'm amazed V1 kept Marco's mom for so long, wtf ???)
Plus V3 had been running Earth the longest, even he wasn't getting so far, and since Earth was top priority, they probably figured to make the top man in charge there a bigger figure, instead of sending in a noob to the planet.
And (final plus) V3 was the one pushing for open war, which the council was probably more in favor of especially after labeling V1 as incompetent.