Rebranding back to Square Soft by be a conflict of interest. As it was the name of them when they were only a Developer (EA published them back then) When they rebranded to Square EA It was because they were doing the publishing for EA in Japan, EA split and Square and Enix Merged. Square being its own permanent developer and publisher.
So Rebranding back to Square Soft which was a developers only name would be... a poor choice. I feel the Square Brand on its own is strong enough as a Publisher Name.
Especially if they go back to the classic RED A style logo.