I always thought that using Aeroplan miles to Hawaii and the lack of availability and the product to Hawaii (think UA's 737 service from SFO as an example) that a purchased business class fare may be better. I often hear on the Premium threads forum fares from YYZ-Hawaii for about $1000 USD. At that price you are barely getting 1 cent per mile. And with a purchased ticket you can probably pick widebody service with flat seats ,I think AA has lay flats on the DFW - Hawaii routes, and better times options to fit your vacation needs. Just my 2cents.

However if you are sitting on a boatload of miles and are short on cash this advice may be poor for you.