Max Pending Challenges

I see your point. But, I am wondering if that is the only solution.

Currently, I don't think there is an easy way to see if a player has pending challenges. If players could see that another player already has a couple of pending challenges, they may be less likely to try to challenge them again. At that point, you could increase the allowed pending challenges to 4 for example.

Just thinking out loud really. I am still considering your request. Either way, I think it would be cool to see how many pending challenges each player has directly on the ladder. What do you think?

This has now been done! There are now limits on incoming and outgoing challenges.

By breaking up the max pending challenges, into outgoing, and incoming, it keeps players from never being able to challenge, or never getting challenged.

If someone always challenges to their max, then nobody can challenge them.
Also, if someone is always being challenged to the max, they could never issue challenges themselves.

If you really want people to play more matches, you should push them to use the "Looking to Play" feature. It reduces declined challenges since the challenger knows when and where a player is looking to play. Some of the most active ladders on this site use this feature heavily.