Ctrl-double-clicking on one of the workers gives you exactly this already.
It should also be noted that some factions' workers (magic, persian) can actually attack.
Yes, and the AI doesn't use the Initiate in magic well because of this. However, doing some testing in the past, I noticed that if the "worker" unit has an attack option, the AI plays the game entirely different, rarely building and focusing instead on morphing units, while instead, if there is no attack option, it focuses on constructing buildings and producing units. Seems to me this was how they determined whether the AI should play magic or tech style. I could be wrong, just an observation with no looking at the code.
