As a MoI user Ill say that all the focus should go to MoI's development. One of the reasons I chose MoI over Rhino is that MoI is "CLEAN".
Dont give me wrong I like McNeel's "Democratic" approach to support every single format, every single Rendering app. etc. BUT from what I have experience there is not many formats supported that you can say "Yes It Works".
On the other hand MoI supports few formats BUT they are all do the job. (also one of the main reasons why I choose MoI).So yes MoI is not just a pretty face.
I also think is very very early for SDK or Plugins, that could lead to the same problems Rhino or Others have. After all as we all know MoI have one of the best meshers, there for you can export to any app you wish for UV, Paint, Rendering etc.(is not always perfect but the best you can get).

That's just my personal thoughts and I think MoI should develop to a Hard Core Modeling Tool. I have also asked in the past for a rendering plugin but happily I could trade my wish for more modeling tools...hehe.