A few reactions:
"I’ll admit that even after reading First Wave #1, I’m still not entirely sure why DC is publishing this comic. I’m not saying that because of quality, but rather the general idea behind it all." - Greg McElhatton
"Does it make more sense for a publisher to put out a bunch of related material as quickly as possibly and bundled as closely together as possible, and thus it won’t matter if anyone likes it or if a series has buzz or legs or whatnot, because the company will have already sold a bunch of books?" - J. Caleb Mozzocco
"...I can’t for the life of me imagine any of these books now taking off or doing better than, say, 5k-ish by month #6; nor do I think these will have legs in collected formats either." - Brian Hibbs
What history suggests to me is that the current comics market isn't interested in shared universes beyond the Big Two (Marvel & DC). Although Image technically casts their super heroes in a shared universe, it plays by loose rules and lets each creator do their own thing, only coming together every few years to produce something like Image United. Readers of Image titles don't consider themselves as buying into a "universe," they only follow Image books that interest them (and successful titles like Walking Dead are set in separate universes). Attempts to launch new shared universes at publishers like Crossgen & Devil's Due met with failure. Wildstorm's shared universe is fighting for attention. There's probably a market for DC to try and sell Doc Savage & Spirit comics to, but by connecting the two together into a "universe" with First Wave as the "spine," that seems to guarantee fewer readers because they'll be afraid to commit to a single title for fear that they'll have to purchase a second to follow the story.
Like me, for example. I'm interested in seeing what Mark Schultz will do with the Spirit, but knowing he'll only be there for three issues and will be taking his cues from what Azzarello's doing in First Wave makes it appear like less of a creator-driven, story-driven project and more of a company-driven, editor-driven mandate. DC isn't publishing a Mark Schultz Spirit comic because Schultz had a vision, they're publishing it because they needed a Spirit comic in the schedule and Schultz had three months free. Or so it appears.