[KevinEldon]

The term 'business value' is hard to measure for any given developer I think. The easiest measure is to say your managers define 'business value' and you deliver what they want or deliver to their strategic objectives, but that equates 'business value' to 'management whim'... if the manager is a perfect guide to maximizing profit then I guess that's ok, but I doubt most managers have that perfect ability to detect how to create profits. Alternatively, you might suggest that some cash/profit measure determines 'business value', but that's both hard to measure and not always strategic... some businesses need the best developers to build the systems that lose money in order to make money in other areas.... it's hard to measure.

With the way you've outlined it I think you've emphasized that a 'Senior developer' is someone who can be both social and technical, that's a good thing and would be very beneficial for any person who can do those two things well... but I wouldn't discount people who are exceptionally technical but need someone else to help them prioritize and define their work and focus.