Currently, I am an mixed signal ic designer.
In previous 4.5 years, I did pure digital design: from front end to back-end.
Now, I started to design some analog design. My area is delta sigma ADC.
I have friends working as digital ic designer, also some working as analog ic designers.
What I found is:
1) There is one huge gap in analog design and digital design.
2) What the analog designers can do, is block design.
3) What the digital designers can do, is the system design.
For one mixed signal chip,
1) What make it more valuable, are those analog features;
2) What make it more success, are those system design.
So, both are important, I think.