How are the drumheads fitting?
I had a '50s Gretsch blue sparkle 4" x 14" Progressive Jazz snare for a few years (garage sale find for $25!). The drumheads fit so tight they literally had to be jammed on with some decent force. It was one of the worst sounding snare drums I've ever played. Very boxy with horrible sensitivity. (I wound up trading it to a friend for one of the BEST snares I've ever heard/had, a late-'70s Slingerland Sound King 6.5" x 14" TDR. Amazing sensitivity.)
I had the same experience using another Gretsch RB snare for some rehearsals. Heads fit too tight and the drum was very choked and dead sounding.
Another friend of mine who gigged with an older Gretsch kit for many years reported the same thing about the snare: The heads fit very tight and he could never get the drum sounding quite right.
The drumhead has to "breathe" a bit on the shell in order for the drum to have life and sensitivity, in my opinion. On that Sling drum I mentioned above, you could spin the head on the shell. This is also one of the reasons I think Rogers is held in such high regard: The drumheads seat very well on Rogers drums in general?a bit loose. The shells seem to be a bit undersized. As a result, these drums are very lively and sensitive.
So check the fit of the heads on your drum...that might be the problem. Another could be that the bearing edges are not true anymore, which would need to be evaluated by a repair person.
Hope this helps,
Charles