A common workflow is to combine several different synths playing the same part. For Sonar and other DAWs this means adding another synth, optionally sub-mixing it and then copying the midi track.
It would be nice to have a synth rack that you could use to add multiple synths to a single track. Reason does something like this with the Combinator.
Basically a synth rack would direct the MIDI input to all of the synths and then combine the audio outputs. This would allow you to treat more than one soft synth as a single composite synth. You'd probably want some way to send or not send things like automation to all the synths globally or to each synth individually as well as knobs to control the individual levels at the output.
System: i7-6900, 64Gb, AMI X99 Carbon Pro Gaming, AMD Radeon HD 7700, Win 10 Pro
PCIe: UAD Octo
USB: MOTU midi express 128, OB-6 Module, Akai MPK-249, Moog SUB 37, Antelope Orion 32 HD, Softube Console 1, iLok, eLicenser
DAW: Cubase Pro, Ableton Live, Sonar Platinum
Plugins: Waves, UAD, Xfer, Lennar Digital, u-he, Reveal Sound, Spectrasonics, SoundToys, VPS, Blue Cat, iZotope, NI, Valhalla, Lexicon, etc. https://soundcloud.com/thomas-helvey