Envy had 50+ people in their roster going into SoO. Worked out reasonably well for them.
Didn't sanitas bring in like 5 social players that had never done heroic before? Making the transistion into 25 is more important than killing everything at this point, gear/"progress" is irrellevant. Now that they are raiding 25, new recruits will be getting a raid spot, not a bench spot, making it far more attractive to join than if they had gotten a "well, we'll use you when we go 25"-spot.