Sharepoint WSS Web Apps

Involved in a situation where there has been some efforts to build a complex line of business application on the Sharepoint platform.

I love Sharepoint and its capabilities for portals or lightweight apps that can take advantage of many of the collaborative capabilities, but there is a point of diminishing return if youre going to have to build an infrastructure of logic and functionality for the type of business workflows that exist in most mission critical applications.

Can all of that be fit into web parts? Can web parts be made to exist as views in an MVC architectural pattern. Well, maybe but its not purposeful as its not intended to be able to do that really. You can do it but should you want to?