Done a lot of reading about the most popular motorcycle routes.... and have also talked to hundreds of other motorcyclists while out on an adventure - - and without question the Trans-Canada Highway is on every motorcyclists bucket list.
The only 'negative' I've ever read about it (this isn't me) is the lack of "Twistys" for very long sections. Sure you know but if not - Twisty's are turns, frequent turns, like you find in mountains. Motorcyclists love those... and so do I... BUT - not as much as the scenery... scenery is priority #1 for me.
Although you didn't ask,
, I think (one of those things where I can change my mind 30 seconds from now), my favorite route in my travels was the 4 Corners area of the USA.... where Utah, Colorado, New Mexico, and Arizona all meet. I even ventured off pavement while in that area and onto gravel and dirt roads... my motorcycle isn't built for gravel/dirt roads. It's a place where even those who are fanatically NON-spiritual will stop, consider, then say to themselves, "The Native Americans got it right".