Hi Daniel,
Thanks for posting here.
I realized you were using Office 365 for Small Businesses. I understand you have changed the default team site address to [domain].sharepoint.com/web, after that, the Team Site button on the header of the portal page would not take effort any more.
Based on current situation, the URL in the address bar is not able to be changed manually. After change the team site default address, customer have to access their team sites by manually typing new URLs. I understand you are one of the true Office 365 Users who would like to share the experience and feedback on improving Microsoft products and services. As to the feature you discussed here, to make it better meet your requirements, I recommend you submit feedback about this requirement to our product team. Many features of current programs were designed and upgraded based on customers’ feedback. Again, thank you for working closely to improve our products and service.
Thanks,
Maggie Li