Interesting topic, platters. My preference is for a lightweight design because I believe Rega are on the right track at least where weight and mass are concerned.
On the other hand both my Rega 3 and and LP12 had heavy platters. In fact one of the most convincing vinyl demos I ever heard featured a turntable with an enormous platter.
It was almost comical in size, could have been 6-8 inches deep. It was rotated by a motor that was housed in a separate box situated several inches to one side via a fairly long thin belt.
My initial visual impression was that this could, in certain domestic situations, be a surefire recipe for disaster.
However the image it cast, via some Avantgarde Trios, was the best I have ever experienced.
Spookily good.
As my memory of the event (London Show late1990s/early 2000s?) inevitably fades, the sheer size and precision of the image being cast remains.