As a Mac user and Logic user I have a feature request for you to consider:
I like the concept of EZ player however this only works with pre-constructed loops. Although in Logic you can use the Piano Roll, Hyper Editor etc to record MIDI it really is not very intuitive for creating patterns especially for those that come from a hardware drum machine background.
The main problem facing Logic users is that Logic cannot output MIDI from one AU plugin to another. Added to this most of the AU drum machine plugins such as iDrum, Guru etc force you to use their own soundbanks and can only load one shot samples.
The nearest and neatest interface is Maschine but firstly I do not want/need all their sound banks and do not particularly need their hardware. Added to this is the fact that the only way to output the MIDI to Superior is to mess with the IAC driver and use it standalone which introduces latency and a whole host of grief and so is also a non starter.
So ultimately I do not know if there is a big enough market for you but an integrated MIDI pattern generator that plays nice with SD would be such a great tool. For it to work in Logic it would have to be built into Superior as I am not sure if it would work inside EZ Player Pro.