I'm not sure what you mean by MIDI limitations of Absynth since it responds to MIDI like any other synth. So it shouldn't really matter if the MIDI data it receives comes from your controller keyboard or your hardware sequencer.
The biggest limitation of this kind of setup is that you can't run more than one instance of Absynth at a time. ...And since Absynth isn't really multitimbral it would mean only being able to play one sound at a time.
Since you are going to use a computer anyway it would only make sense that you invest in a simple host/sequencer program. It will be a much better setup than trying to control a single soft synth with the hardware sequencer. Think of it, you want to use several sounds at once and without a host program you're kind of screwed. In this case anyway. Not to mention the fact that software sequencer programs are much easier to use than any hardware sequencers- period. Just something to think about.
cheers,
[This message has been edited by 3351 (edited 10-20-2007).]