It's not so much ease of communication as ease of travel as well as size that to me determines whether a region should have a full Chapter or not. Since Ju-ji's Hall is right next to our home region it would make sense to just expand our main chapter there.
Another thing you are forgetting is that Chapters have a bigger chance to deviate in their beliefs. Right now we are fine because Martyris is alive, but once he kicks the bucket the Pilgrims will no longer have a final definite answer on any matter. So keeping the number of voices and influences to a manageable level is something we should consider.
Also, I want to see what each level of commitment looks like, since the blurb implies that they would play differently.