As far as MVC.
I used that architecture for a big project a few years ago.
Not sure it really applies to a small shop.
UI in Acad programming is mainly dialog box that collect user inputs in a "per-document" context. Patterns like MVP/MVC make this kind of UI development unnecessarily complicated in most cases, if the UI itself is not that too complicated. It may make sense when the app lives in Acad's application context, such as a modeless form/paletteset that deals with data accross drawings, or holds data from sources other than loaded Acad drawing...