It would be great to have the good old swing 8ths playback option in 2.0 too (see here).
A "samba swing" option would be very good too. Samba swing is analyzed here http://artatom.com/diagrams/Pandeiro_Samba.html and affects 16th notes if the song is written in 4/4 (or common time) or 8th notes if written in 2/2 (or alla breve).
Back to jazz swing, the swing ratio could also be made adjustable by the user, from straight eights to 3:1 (first and fourth 16th). See http://en.wikipedia.org/wiki/Swing_%28jazz_performance_style%29#Types
Maybe swings should be enabled by default in jazz and samba templates.