Clan recommendations give preference to clans that the player can join immediately (open clan, player passes rank requirement) and are more powerful (members, wins, etc).
We see the clan recommendation system as a way for beginner-to-intermediate players to quickly meet each other and form clans. The Expert clans may choose to stay in invite only mode and recruit players via forums and chats. The advanced players that they are looking for will know where to find them
If you are a clan leader and are looking to recruit a sizeable amount of players, consider setting the clan type to “Open” for a while - the rank requirement will help you manage the bulk of the irrelevant applications.