[Shop-talk] Diverter valves

[eric at megageek.com]

Can someone please tell me why diverter valves are built to leak?  I mean, 
why don't they have a ball valve on them so all the water / pressure goes 
to the shower?

Is there a reason I can't add the ball valve myself?

TIA.

Eric P
"Be as beneficent as the sun or the sea, but if your rights as a rational 
being are trenched on, die on the first inch of your territory." Ralph 
Waldo Emerson