The camera market is really all about lenses, not so much bodies. I'm not sure that any lens assets come with the brand, Zeiss would be the one making the bucks, at least, they made lenses for the Hasselblad I owned. I'm not sure if Canon and Zeiss are on very good terms.
If a lens factory and MF designs came with the deal, Canon might be more interested. The list of valuable patents is another asset that would determine if a acquisition were worth considering. Finally, the Brand Name can be a very valuable asset. Hasselblad certainly qualifies there, the name is worth a lot, but the Canon brand is worth 1000 times more, so it would not be a step up for Canon.
On the other hand, Phase One will not be recognized as a camera maker by many who would know Hasselblad. Sony is a valuable Brand name as well, but their camera division could benefit getting away from Sony's reputation for poor service.
That said, I'd like to see Canon do it, even though it would not be a big profit maker, Canon could use the name and their huge marketing network to sell a lot of cameras.