Bard's one dimensional abilities.

Bard is not a very good support at the moment because his kit is very one dimensional. What makes a great support like Thresh is how every one of his abilities can be used in many different ways. Q can be used to stun someone at a distance or it can be used to hook->dash in->and engage. His lantern collects souls, can be used to save allies, and shields allies. His Ult can be used to escape or to box people in. His flay can push people away or pull them back towards him. Etc. Every move has a million uses.

Then you have Bard. His Q is CC. No other way to really use it. His heal is a heal and MS boost. His tunnel is a tunnel that can only be used if he's standing in front of the wall. However his ulti is definitely more in line with the "multiple uses" idea that makes Thresh so successful. If his whole kit could be like that then he'd be much better.

A change as simple as making his Magical Journey like Rumble's Ulti and letting Bard put it down from a distance in any direction he chooses would allow him to pull off Thresh's lantern/jungler-style ganks without needing to leave lane... or maybe it could suck up chimes from a distance like a giant vacuum! His heal giving an enhanced MS boost if you cast it directly on someone would give players a meaningful choice between putting it on the ground or targeting someone directly. I dunno just make him less binary. As of now he basically has two moves in combat, Q/W and his magical journey can only be used in very specific situations unlike Thresh's lantern and it only has that one use. He needs some meaningful choices you can make with his kit. He'd just be much more versatile if players could say "should I use W this way? or THIS way?" more often other than with just his ulti.