Is "ease of use " or functionality of a system - like an ERM, CRM or website more important in system design ? has this changed over the years ?

Of course, Now GUI is the foundation, then system functions comes later. 

Look - I agree 100% with  Chris Charistas I could not explain and detail it better myself.

The increasing importance of ease of use of an application has dramatically increased demand for UX designers and Usability Engineers. Ease of use in is an important factor that determines if an application (or website) succeds or fails in regards to user adoption. 

There are simple principles that if every designer would follow, applications and websites would be more appealing to users. You can refer for example to the 10 Heuristics for User Interface Design (Molich / Nielsen) which describe what principles an application is suggested to follow in order to be easier comprehended by the user. 

Many powerful applications have been designed that eventually failed because they missed the ease-of-use target, hence not becoming eventually a tool for the end user. It's a shame spending so many hours developing functionality but forgetting about the way the end user is going to interact with the application.