If I wanted to get from Edmonton to Calgary by way of Jasper, Vancouver and Banff, this is the way I'd go:
Gets you Jasper, but instead of the busy run down the Coquihalla, you divert through Lillooet and come down via Whistler and the Sea-to-Sky. It'll be very twisty and rugged (with spectacular scenery and huge mountain vistas) from Lillooet down to Whistler, then busy but insanely scenic down into Vancouver on Hwy 99/Sea-to-Sky.
On the way back, you again dodge the Coq at Hope and instead stay south along the border, checking out the desert in Osoyoos. the farms through the interior, stopping at the hippie enclave of Nelson before heading up Hwy 95 to 93 and up to Banff. If Banff isn't a must-do (and unless you're stopping to do some day trips, it really isn't), I'd instead go east on 93 via Fernie and come into Calgary via the foothills and high praries to the south for a nice palate cleanser from the endless mountains.
These routes will still let you pile on miles, but will also offer better and more varied scenery with a lot fewer trailers to dodge. I know you like superslab, but a lot of the Trans-Can through BC isn't shut-your-brain-off multi-lane, it's single-lane with passing zones and needing to keep your head on a swivel for frustrated passers desperate to get around trucks and RV's dragging on uphills. Not dissimilar to the single-lane stretch of the Trans-Can between Thunder Bay and Sault-Ste-Marie, with limited visibility, hills and slopes making for long stretches with no passing.
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I totally agree with the above who suggest making time for Vancouver Island if possible, but you'd definitely need at least a couple of days to do it right. The ferries are totally fine, especially on a bike where you get placed at the front (in a car, reservations are near mandatory if it's a busy route, on a bike they're nice but rarely needed). This has a double benefit of being the first to disembark and get ahead of the traffic crush, but make sure you fill up before you board, or you'll watch the crush start to pass you at the gas station.
Vancouver Island is also a place better suited to exploring and taking your time, as the geography means the Island Highway (Hwy 19) up the east coast is the artery, with roads branching off west but usually to dead ends, meaning loops are hard to do. The route up the Sunshine Coast and to Powell River is also unbelievably spectacular (with the best twisty road in Canada along the way in my opinion), but there's only four sailings a day from Powell River across to the island at Comox, so timing can be complicated if you want to make it part of a loop over to the island.
