I would skip Vancouver and spend more time on the island but then when I vacation I like to see nature (shopping and tall buildings are about the same there as there are where I live).
Where are you going on the island? (it has lots of different cities and things to see)
Explore the best of Victoria, Vancouver Island, the Gulf Islands and the Sunshine Coast of BC, including Sooke, Nanaimo, Campbell River, Port Hardy. Tofino, Comox Valley, Pacific Rim, Saltspring Island and Quadra Island.
Tofino is a fav.
As cities go Victoria is beautiful and a great place to wander around; check out the ocean, shopping, legislative grounds, etc.
Stanley Park, Vancouver's first park, is an evergreen oasis of 400 hectares (1,000 acres) close to the heart of Vancouver's downtown core. Its natural west coast atmosphere offering a back drop of majestic cedar, hemlock and fir trees embraces visitors and transports them to an environment rich in tranquility.