From previous posts, I believe that you are an ATC'er, ferris, is that correct? Because it would appear from your post, and those of RTB RFN's that ATC are not aware of the training that we pilots receive wrt TCAS.
And that is something that needs to be addressed by both your side, and ours.
From the pilots' perspective, a TCAS RA should ALWAYS receive priority over an ATC directive, (accompanied by a transmission at the time of "TCAS climb/descent.") - although they may be totally conflicting, as was the case with the Uberlingen mid air.
It isn't always possible to obtain a visual on other traffic, and especially in low vis conditions, or at night, next to impossible to determine whether an aircraft is at the same level, or even 1-2,000' higher or lower.
TCAS RA's are a "last resort" manouvre, where there has been a breakdown in separation - whether under radar coverage or outside.
"TCAS was not meant to be used like this" - this is PRECISELY what TCAS was designed for, however TCAS was NOT meant to be used INSTEAD of ATC radar coverage, it is meant to be an EXTRA Safety buffer. I believe all ATC'ers and pilots would unanimously agree on that - except perhaps for our adventurer, Mr Dick Smith!
Class E airspace is DANGEROUS!