Chances of the monument getting defaced
Considering the location I've seen mulled over here the most is the grounds at War Museum, I'd tend to agree with you. Remember, the grounds are used throughout the summer for various music festivals, and that would make the Mirage Monument a VERY easy target for the various "individuals" these festivals attract. One exceptionally charismatic "Anti-Bush sponsored war" rant from one of the red-eyed longhair'd "artists" is all it would take for the thing to be smashed to bits.
I'm not opposed to the idea of an Afghan War monument in Ottawa, but the monument we're speaking of was, in essence, built FOR THE SOLDIERS of Canada in Afghanistan. With that in mind, I actully believe it should be relocated to the CFLRS, for every new recruit into our Forces to see and appreciate. Call me what you will, but I believe that would be the most effective, and proper location.
I know many people think "Trenton" because that's where the repatriation happened. Consider this; the fallen began their lives as soldiers at BMQ at a recruit school. This war has shown what our soldiers, and country for that matter, are made of and how dedicated they are. This is where the "making of a soldier" begins.