Bare with me people
In the latest chapter shizune confirms that the black rod is a chakra receiver, Tsunadai came up with two possible conclusions
1) They all move according to these chakra signals they recieve
2) Maybe it's a way for them to transmit chakra between them
Chapter 421 page 15
So what we learn from this is that pain needs to keep recieving chakra or he won't function.
And let me bring back a certain chapter to give you a little hope.
Chapter 383 page13
At the bottom of that chapter, pain admitted that he would of never have won if jiraiya knew about his secret. Now according to that statement a single ninja who is highly skilled and intelligent is capable of taking out pain if they have knowledge of his secret.
I know a lot of ninja's in konoha aren't on jiraiya's level but a few of the good ones working together should make up for the strength and skill. And konoha is figuring pain out very quickly, once they know about him, I guarantee they will be able to finish the job.
I don't even think naruto is needed.