Hi, I am on Jakob's team of User Experience people and am one of the Interaction Designers.
You got a point that UX is more than UI. That is why we do more than UI
We have been part of defining all the Roles you may have heard of in our Role based applications. We work with marketing to define branding, we are a big part of the conference called Convergence where we have a lot of interaction with Customers and Partners.
We are also part of the planning of new features, of gathering requirements etc.
Of course we do UI. That is what we spend most of our time on, because that is a pretty big part of what people experience
The the comments about Jakob's name, trust me, he gets that all the time. Funny thing is that both Jakob Nielsens are from the same university in Denmark.
The obvious reason why Microsoft is one of SAP's large customers and is not using our own ERP systems is that our ERP products are built for the mid-market. I.e. midsized companies and you can hardly call Microsoft a mid-market company
We do not want customers the size of Microsoft for our Dynamics products. Our products are not geared to that size because such companies have a need for a different level of functionality. You might as well ask why SAP is not huge in the mid-market. And
the answer is that in many cases SAP is overkill for that segment of businesses.