A new SharePoint Online administration portal is being deployed; as usual available first for First Release tenants.
A link (Try the new SharePoint admin center preview – pointing to https://<your tenant>-admin.sharepoint.com/_layouts/15/online/AdminHome.aspx) to the new SharePoint Online administration portal will be shown (when available) from the current SPO administration portal
If you want to give a try to the new portal, just hit this link.
This portal will then gives you some activities/usage report as well as information related to SPO (like related message or dashboard health)
When accessing the Site Management section, you will have the list of all site collection created as well some details like the site template used, when created and the last activity
NOTE you will be able to export this list to Excel; seems there is still some work to do there as the report is currently empty
When you select one site collection and hit the Information button (top right) you will get more details related to this site collection, and if it is not locked (as for deleted site in litigation hold) you will be able to change the administrator(s)
With this new SPO administration portal, you have a quicker/simpler access to the Site recycle bin
Finally the settings currently available with the new portal are limited to the Lists & Libraries experience or the Notification; nothing for the global SharePoint configuration
Obviously this looks like a very early stage and lot of settings/options are missing or not working