The only difference is on the device side. SVDO is not an issue. The HTC works fine in 1x and EVDO mode, and handles SVDO just fine. It is only LTE that EVO has had LTE connectivity issues with.
Even though the HTC has multiple LTE antennas, it doesn't interact differently with the site than all the other MIMO Sprint LTE devices. Two diverse antennas on the device have two separate data sessions going on with the LTE site. If there are any flaws in that setup, it would be an HTC issue. Sprint is not doing anything unique that no other LTE MIMO carrier does.
Robert