Well, as I don't have a boat in Birmingham yet my opinion wouldnt be based on any actual experience.
I think any investment in the canals would be welcome - having lived in Brum for 10ish years some of the canal network looks like its been abandoned. I hope the new money, if and when it comes, would help to redress this.
Narrowboats played a crucial role in Brum's development yet its not something Birmingham takes much interest in beyond encouraging tour boats. I think there needs to be more of a focal point for boaters, esp liveaboards and narrowboat-based business, in the city.