A classic example 'of one size does not fit all'!
How ridiculous that a Unit awaiting one aircraft should require two controllers, one in tower and one in radar. A radar rated tower controller with modern radar displays can easily position an aircraft on to an ILS.
The rule was invented in the days of radar controllers working in darkened rooms. It was clearly an appropriate rule in those days but not in 2015!
The use of radar by a tower controller merely requires appropriate risk management, followed by strict application of the procedures so designed.
I would rather have the tower controller providing a limited radar service [to limited traffic] than have the tower controller reading a newspaper, watching TV or merely immersed in conversation......all possible distractions to the job in hand.
H49