The drive between the Rockies and Vancouver is indeed spectacular. However, there are spectacular views everywhere around the Rockies and driving 10+ hours straight can be very tiresome. As for flying into YEG, that is debatable if it is a better option as opposed to YYC considering it is only an extra 40 km between YYC and Jasper (city) vs YEG and Jasper.

If it was me I'd fly into YEG or YYC (depending on flights available) and spend a couple of nights in each Jasper and Banff but staying the last night at Banff area and then fly out of YYC to YVR. Since Banff is relatively close to YYC, flying will be faster and less tiresome than driving in this case.

Besides Banff and Jasper parks there are also the Yoho, Kootenay and Glacier parks which are worth the visit if there is time. There are plenty of lakes to visit, trails to hike and mountains to hike and climb in all of them. Not to mention the great vistas to behold.

Another possibility is taking a bus tour to the Rockies from either Vancouver, Calgary or Edmonton if you are so inclined. That might be a great option if you don't mind group travelling and all what that entails

Finally, Vancouver also has many attractions as well and if your SO like outdoors you might consider visiting Vancouver Island as well.