My Shadowrun group just recently grew from 1 GM and 2 players to 1 GM and 3 players. More recently one D&D group shrunk by 1 co-DM/player down to 2 players, 1 DM and 1 player currently occupied in the army for the next few months. After a time where some players apparently wanted to decide whether or not to attend a session 5 minutes before it started I decided to forget about them and stick to the players that attended regularly. It makes scheduling much easier, and playing in such small groups also makes for more "spotlight" time for the individual players.
If your 7 players group is making it hard to schedule game sessions, then I heartily recommend shrinking the size of the group down until the only one left are those that will attend regularily.