The release notes for MorphOS 2.1 are quite extensive, but the most important changes are a sound driver for Efika boards, a 2D driver for the XGI Volari V3XT graphics card, and a virtual CybergraphX monitor, so you can use MorphOS through VNCServer without a video card.
Related to this is news from MorphOS core team member Piru, who has given out some details about the Mac Mini port of MorphOS. It now runs on all revisions of the Mac Mini, as long as it has a Radeon video card. He also uploaded a nice screenshot to prove their hard work. Sadly, he couldn't give a release date estimate.