That sounds reasonable, Kovash.

There probably aren't that many people out there with more jutsus or more chakra than Oro. So every time he took a body, he'd be getting weaker, and that's no fun.

Also, if you recall, he told the person he's in now that his strong will would continue on in him. I'm assuming that this implies some kind of merging.

@The Heretic Azazel
What makes you think these guys were mediocre? I'm sure he wouldn't have just taken anybody. They might well have been the strongest fighers in the Sound village.