Perhaps since the manga is probably getting great reviews and selling a lot of copies (not actually sure, just my guess), they might be trying to set up for a new arc after this one... This new leader that's behind the scenes doesn't seem like he's tougher then Jinsuke though. If he was then he wouldn't be biding his time and getting others to weaken his forces... If he was stronger then jinsuke then he could just walk in there and kill him, they do se him as an ally afterall, so getting close wouldn't be a problem. So i think you might be right, he seems more like a political man with strong followers under him.