Thanks for this article Vincent, I think it sums up the role very well. As a datawarehouse developer/consultant, I am often asked to perform all of the tasks you mention. While it is true I can perform most of these tasks reasonably well, I definitely agree that this is a specialised role and the need for it is growing.
I wasn't ready to completely agree with your comment regarding a DBA being best suited to moving into this role. I believe an experienced developer could reasonably easliy step up into this role and would be able to learn the 'hard' skills of recovery models, backups/restores, DBCC stuff etc quicker than a DBA could learn the 'soft' skills of DW concepts, SCDs, tuning as it pertains to DWs etc. But the problem for a developer who moves up to a DWA role is that they will always (or at least I would) try to get too bogged down in the detail of the underlying processes, ETL procedures and specific reports, and therefore possibly have a harder time keeping focus on the big picture stuff. Given this, I think you're right, a DBA is best placed to move into this role. But it would have to be one who is ready to completely immerse themselves in the DW world in order to be effective.
I am hoping some (many!) manager-types will read this article and start to think about this role as being distinct from a 'transactional' DBA, and therefore think more seriously about putting resources into this area.
Good article, keep 'em coming.