I found myself wishing so many times to be able to record a pattern into the sequencer, which is then being repeated, but having the possibility to "override" the notes in the sequencer by what I am playing on the keyboard (without changing the recorded pattern). So you could play Solos and varyiations inside a sequencer riff, which thens resumes, when no more Notes are being received from the Keyboard.
Is that a common feature on other synths? I imagine it not to difficult to realize software wise...
