I'm not sure why you'd employ a rule that only allows for a maximum of 10 players tbh. A lot of clans have many clan members that would like to participate in the event. With you limiting the maximum amount of participants, there'll be a lot of people who'd been looking forward to the event that won't be able to participate.
Clan League in itself only comes once a year, and is an event where a lot of members look forward to participating in. It's an event where a lot of players go out of their way to comeback to the game to hang out, practice, and compete with their clan members. With you limiting the participants to 10, clans won't be able to enjoy the festivities of the event to its fullest.
By limiting the participants to 10, you are also making it unfair to the clans themselves. With this rule in place, clans will have to choose representatives out of the many members they have. This can lead to conflict within the clan about the players participating in the event. Members not chosen will feel excluded as they are not able to participate in the event, and unnecessary conflict can arise. Additionally, if conflict were to occur because of who's participating and who's not, it can negatively impact the overall performance of a clan with unnecessary distractions due to the implementation of an unnecessary rule.
Clan League had also been the one of the most if not the most prestigious community event in the game. The more participants playing would only lead to the event becoming more exciting. Right now, not a lot of people play the game, and limiting participants to the one event where people actually want to play the game just doesn't make sense.
The event's name in itself is "Clan League", and most clans are not solely composed of 10 players. Just let the clans decide how many players they want to play and compete in the tournament. There's no need for there to be a limit on how much players can participate.