Mazda Canada is taking a HUGE risk in bringing the Mazda5 to Canada (in many ways, a bigger risk than the Pro5 - which obviously turned out to be a tremendous success). The Mazda5 is a mini-minivan by N. American standards. In Europe, Oceania, and Asia, this type of vehicle is very popular - in fact, the Mazda5 is the replacement for the Mazda Premacy (which never came to N. America).
Having said that, I understand why Mazda Canada is taking this risk - N. American minivans are going bigger and bigger and the MPV is no match (nor would it make business sense for Mazda to go bigger). Even though the Mazda5 is not a direct MPV replacement in all markets (as I said, it's a Premacy replacement), Mazda may have decided to go another route and focus on going smaller while others go larger. I know for a fact that both the Premacy and MPV will be stopped in the UK when the Mazda5 is released (so it'll be interesting to see what happens to the MPV in N. America).
It will also be VERY interesting to see if MazdaUSA brings in the Mazda5 - when asked about the MX-Flexa (the concept of the Mazda5), the president of MNAO said that any vehicle that fits the Canadian market would probably fit US as well.
One final thing, the Mazda5 is based on the Mazda3 platform (with an extended wheelbase). The Mazda3 2.0l engine is already confirmed for the Mazda5 in Europe. As such, I'm sure the Mazda3 & 6 2.3l will definitely be one of the engine choices in N. America, but will it be powerful enough for N. Americans?