lol as if bard is op.
The "mobility" comes from his chimes that drop randomly around the map,he can't get the speed boost whenever he wants.
His heal isn't that strong,it needs some time to built up before it really heals a good amount of health(and you can step on it to destroy the shrine),ofc his heal is strong early on if he maxes it first,but that goes for about every heal ability in the game.
When he goes through a wall,then simply go after him.EVERYONE can go through his portals,even enemies.
His ultimate has quite some travel time and affects everything and makes it invincible,this applies to bards allies and enemies,meaning that it can easily mess up.it also doesn't deal damage.
And wow he has 2 different ways to build his items,why would that make him op?Just because he has 2 different options doesn't mean that these options are better than the options of the other champs...