Big changes are incoming to the way most guilds are likely to approach their daily operations. As WoW Insider reported earlier today, new, Black Temple-level gear will be available via Badges of Justice come Patch 2.4. The vendor is on Sunwell Isle, and probably won't be all that difficult to get to (selling raid spots, anyone?). But the items themselves are probably going to be VERY expensive, on the order of 100 Badges and up I'd imagine, which would take several weeks of farming raid instances to acquire.
So, that begs the question... are Heroic Dungeons going to see a much larger role in the average guild's list of priorities, come Patch 2.4?
In the guild I am currently in, there is a standard hierarchy that is applied to certain objectives in-game, and which seemingly never fail. Daily quests are easily at the top of the list, with many guildmates spending hours logged in on mains and alts for the sole purpose of completing them. When those are done, PvP then takes precedence with many taking to the Battlegrounds to grind Honor Points. A distant third are the lonely Heroics, which at best are only run once a day by a small minority of the guild.
Currently, it's understandable why Heroics aren't that big of a deal -- the motivation to run them, the Badge of Justice, drop like candy in raid instances, which are scheduled, weekly runs. For example, where you would only receive 3-4 badges in any given Heroic, you would receive over 20 when clearing Karazhan. Sure, the raid takes more time, but it's time set aside and planned for, which is not the case for Heroic Instances (at least not in this guild), and hence why Heroics are a distant third to dailies and the Battlegrounds.
However, I can't see that approach remaining popular once extremely high level gear is introduced via the Badge-vendor system. Even when raiding several 10 and 25-mans a week, it would take several weeks to acquire the number of Badges that will probably be needed to purchase these BT-level items. Complimenting the raids with Heroic Dungeons, which are not limited to a lengthy reset time-table, would be a great asset in acting to acquire these items asap. Thus, it would be very unreasonable for a guild to not make running Heroics (and gearing up their members for Sunwell) a much bigger priority.