I was thinking this could be a cool way to cross the River. Here's my crazy idea:
The NCC is thinking about putting a look-out at the foot of Bank Street anyway, so why not make it a hub?

from ncc-ccn.ca
A visitor centre here would be about the same distance to the Peace Tower than the existing ugly one, and the tent where all the tours start is actually along the way.
Aerial tramways can carry about 150 people, like this one in Austria:

from discover austria
A few cities use aerial tramways as public transport, ie New York City, Portland OR.
The cables would be unobtrusive to the view. On the Ottawa side the tram could come out the side of the escarpment from a structure that looks like part of the cliff, and on the Gatineau side, the terminal could be built into a new building, maybe incorporated into a new Museum, like this cool terminal in Portland:

from ETH Life intl.
Tourists would love this thing, but i could see locals using it regularly. Civil Servants could go from the Portage complexes to the Ottawa govt offices quickly, courriers on foot/bicycle could extend their range, shoppers could shuttle between Sparks Street Mall/Bank Street Promenade and Place du Centre with ease.
It's just a fantasy I wanted to share....