Adding skill to League
Just two gameplay or game mode suggestions to try and add skill to league.
Friendly Fire - Make every projectile hit the first thing in its way including teammates.
Not sure what to call it - This could technically go into the first one but parry shouldn't be a unique skill. Projectiles should be able to collide with each other allowing players to block enemy spells by hitting them with their own spells.
First Person - This would be interesting but considering how most of your art is actually only 2D it would require large map updates to be possible
Not going to elaborate on each one. They are fairly obvious as to how they should be implemented.