Is it no longer possible to split by symbol on to a new track

You mean split a Figure by symbol type?

Drag clip into embedded libarary, goto library page, right-click 'split by symbol type' creates multiple phrases that you can drag anywhere you want

The old command created new tracks (instruments) which could be very intrusive and mess up your arrangement. It was also clumsy to undo. 

Using the library as a clipboard for splitting phrases is more flexible. You  can also do that right after you generated them with a Factory, for example.