For a vast majority of guilds that are not yet 12/14H, WoD will be out before they get to garrosh. Of course there will be exceptions, some guilds started late, havent raided etc, whatever the reason can be, but that does not change the fact that those are exceptions. If you got even lower to about 8/14H, those guilds have about 24 months of progression to go in the in their current pace to reach Garrosh.
A guild that have been actively playing and progressing since SoO came out will not clear the content without major nerfs unless they are currently 12/14 or above.
People really underestimate how much easier the first part of SoO is than the later parts. If you are not breezing through the first bosses then you will not down Garrosh. Period.