I've sort of lost track as to where all of this is going. There is a pretty strong correllation between WM and VIQ (.65) and (.80) with other measures of span and D'Esposito and other s have mapped this onto dorso-lateral prefrontal cortices since the mid 90's. I'm not sure I understand what point you are making other than to say that it is moving more with cortical measures such as the WAIS instead of the other WMS scores which I guess should be obvious.
I'm also not sure about the other post regarding the CMS since it shares almost identical data to the WISC-IV in that 70 on the WISC-IV will give you mid 80's on the CMS and 130 will give you 115 or so. The technical report is available through Harcourt. It doesn't move any differently in a normal, unimpaired population than the WMS in adults.
As for the WMS in general, it is not fair to rate the goodness or badness of any test based on these types of questions. To understand the WMS is to know it's average scores in normal and impaired populations, I'm not sure you will get Cohen's d of 2.5 or higher as you would with some screening measures, but people should not get so frustrated that the average mild DAT scores are in the 70-80 range either. Is this the best test with demented patients? That depends. Other NP tests suffer similar issues, with the MAS colapsing all scores for subjects over 75. In cases where lateralization is an issues, you have more problems picking outside a standard battery such as RAVLT/RCFT that while normed together, do not reflect the same paradigm and the RCFT is so loaded on Exec Funtion in the copy portion that the memory portion can be rendered meaningless. Others are simply not normed together.
In kids the CME recognition functions as an all or nothing measure with 30/32 normal and 29/32 impaired, which implies significant floor issues.
With the RBANS, I can't tell you how many 55-60-y-o bright folks with minimal memory issues come in for evals, get WMS scores in the 110's or higher and then 80's on the RBANS becasue of these floor issues in a younger sample, which one is the problem in these cases. When mild DAT scores 80 on the WMS, 55-60 on the RBANS memory and a DRS of 120, what is that. I have no problem saying mild impairment since I understand the ceiling and floor issues with each test. The fact is that you CAN'T get impairment on the WMS Faces if you are older than 85 because you'd have to score below chance, which would imply malingering. But in a TBI sample these problems do not occur.
In large part, these are the main reasons why we teach pathology in grad school for NP and psychometrics as opposed to instruments, because there would be no reason to give the WMS in a case where memory problems are not modal deficits for the disorder under question, which we still don't know from the OP.
Those who learn only the instruments are lost on these more complex issues and then blame the tests for their misunderstanding of the findings as opposed to their limited understanding of the pathology they study.