HI!!
I wanted to suggest this feature. May create a new pane in preferences dialog with list of predefined variables. This certainly would significantly simplify most of file operations and converter filename templates. I give an example: everywhere in file name formatting strings I use same expression for track number.
$ifgreater(%tracknumber%,0,$num(%tracknumber%,$ifgreater($trim(%totaltracks%),0,$max($len($num($trim(%totaltracks%),0)),2),2)),$upper($trim(%tracknumber%)))
Defining a global variable such as tn containing this pattern would be also very powerful if I decide in future to change this tracknumber formula to something yet more obfuscated, to just change the global variable instead of editing all presets individually. I suppose this feature isnot too complicated to implement so I hope Peter or some other developer will make it come truth