I can tell you that this arena will definitely be a boon for the city. We love our hockey in Michigan, we take it seriously and the larger the arena, the greater the number of people coming to the city will be. Unlike NFL Football, a hockey season is long and has many games. This article doesn't attempt to look at the ROI of this for the city, simply the costs. Street lights? Yeah, that would be great but it will do literally nothing to bring more suburban money in to the city.
It has the added benefit of being able to raze Joe Louis Arena, the worst hockey stadium in North America, which also happens to sit on awesome real estate on the river. Getting it out of the way will allow us to expand the riverfront district that much further, which I think will encourage even more development. The arena is expensive, but I have a hard time seeing it as a negative.