I just wanted to add my +1 for allowing periods in S3 bucket names within Discourse. AWS itself allows (indeed instructs) this now for CNAME-based access to S3 content, and provided the s3_cdn_url setting in Discourse is utilized so far as I can tell the previous issues encountered around HTTPS are rendered non-problematic, at least when services such as Cloudflare are used (as @uppfinnarn notes SNI-based SSL certs solve this issue).
Might it be possible to revisit this in an upcoming release?
Thank you for a great product!