I am looking forward to having Sends for MIDI tracks (like you can for Audio tracks). That way you can have a single midi track sending MIDI data to more than one synth or MIDI out port as a time. This would open up lots of possibilities for layering synths.
One way I can think of doing this currently, is to copy and paste (link) a clip to a second track that is routed to a synth. Because they are linked, any edits you make on one clip would replicate to the other copy. However, 1 MIDI track to multiple synths via sends would be so much easier..
I think there is a feature request for this somewhere in the plethora of feature requests.