I am one of those LTMA Controllers you mention. To me, on the ground, it seems that sometimes we are talking continuously, most times it is because we are very busy on that sector and it is fully split.
Sometimes though it is a very small busy period which we can see will be over shortly. Flow control sometimes seems to be 'Bunch Control'
Is the R/T as busy in other places in Europe/USA?
What do you pilots think?