Boomerang to Seattle
I used to live and work in Seattle(Amazon) back in the day and moved to the Bay Area in 2012 with a different job. After a couple of years on that job, I boomeranged back to Amazon in the bay area. A few months later my boss in Seattle wants me to relocate back to Seattle with the reason that it would give me more visibility within Amazon because it's the head quarter. Does it make sense because I'm not being given any financial help in moving back to Seattle. Is this something I should consider?
You should make this decision based on your happiness re: Seattle or bay area. If you decide to move, I would ask for relo assistance, at least to cover your moving expenses.
Since you will likely change compensation between Bay Area and San Francisco you should ask for relocation. Of course if you go through internal postings most have domestic Relocation included.
Ask for relocation