Dean_Gross securitycenter.microsoft.com is the portal for Microsoft Defender ATP, while security.microsoft is the portal for Microsoft Threat Protection.
MTP will be the defacto product that will encompass all of the existing M365 Security Workloads (MDATP, AATP, OATP and MCAS).
So yes, MDATP portal will be migrated to MTP soon.
More info here:
Dive deep into Microsoft Threat Protection: See how we defend against threats like | SECO20
https://www.youtube.com/watch?v=NogNroy0FSM
Announcing Microsoft Threat Protection
https://techcommunity.microsoft.com/t5/security-privacy-and-compliance/announcing-microsoft-threat-protection/ba-p/262783
Microsoft Threat Protection
https://docs.microsoft.com/en-us/microsoft-365/security/mtp/microsoft-threat-protection?view=o365-worldwide
Turn on Microsoft Threat Protection
https://docs.microsoft.com/en-us/microsoft-365/security/mtp/mtp-enable?view=o365-worldwide