Some you can, some you can't. RNAV SIDs are designed to different criteria than conventional SIDs.
No argument with the second part of your statement.
But it's hard to imagine a set of manoeuvres involving radials, QDMs and height/climb/speed restrictions (which is a pretty good description of what a SID is) that couldn't equally be defined with fly-by fixes, tracks, level/speed constraints and path terminators (i.e. as an RNAV1 SID).
Which ones did you have in mind that can't ?