On the surface, I'm thinking so. Outside of the diagrams, there's nothing that can't be answered quickly.
I see Gaming.SE as a completely different, non-conflicting thing. Strategy guides aim to tell you about everything in a game. We're here to answer specific questions (that you can't find with a quick Google search preferably). Sometimes a strategy guide doesn't cover what you'd want to know, or there may just be no strategy guide for a particular game.
Really what we aim to "replace" is the myriad forums out there dedicated to gaming strategy/non-technical help. We feel like the Stack Exchange engine is better suited to asking and answering questions and keeping current than the clunky old forum paradigm. No one likes to scroll through 35 pages of forum discussion from 2001 that may or may not contain the answer you're looking for.
If GameFAQs, which has existed for years, hasn't done away with the need for guide books (they are most definitely not "cheat" books), then I highly doubt that this site will do it. Especially since that site provides something much closer to what guide books provide (walkthroughs) than this site does. And it has forums for your desired "quick question and answer" functionality as well.
Actually, GameFAQs is much better than this site for most games because right now, I rarely see any questions getting answered here that aren't the "top" current games out there (SC2, Civ5, WOW, Minecraft and now Black Ops).