Sorry: plain language reply, G. I've been marking MCQA tests part of the day!
As a helicopter driver, I'd like a 'TP Rating' on my JAR licence that would cover me for all SE/ME types provided that I had a valid LPC on any aircraft type in each group. This would allow flight test, ferry, positioning and demonstration flying; I would not expect to exercise CAT privileges without a valid OPC for each aircraft type.
This would give some professional flexibility. Think the French have this sort of system in place under national regs.
Similar sort of thing for the plank drivers and FTEs. (FTEs to hold an FE licence?)
Graduate tps or those who had done suitable 'apprenticeship' to be accorded the licence privilege.