I've been playing as Bard pretty exclusively since I got back into LOL about a week ago (I've taken breaks on/off since beta). Just normals, so what I write here might not be worth anything.
In the beginning it was pretty hard to Bard. But generally speaking now, I feel like I do pretty well in 8/10 games. I think part of the problem is the way people imagine him using his skill set. I don't roam very much unless my lane opponents have recalled. Otherwise, I just stick to warding and picking up chimes in the river. The necessity of roaming may be more noticeable in upper-tier ranked play, but I don't really know how many people here fall into that bracket.
Bard's got a great kit, IMO. He's got a stun, lane sustain, powerful mobility, pretty strong auto-attacks with a slow, and the ult. I think the advantage of his movement and movement-impairing abilities is probably his greatest advantage for baits, distractions, scouting/warding and maintaining a solid position in team fights. Mostly, it feels like he was meant to troll the other team.
Something that I've noticed: When an opponent enters the portal, that's like 2-3 seconds that they are not attacking or anything. They are essentially out of the fight, and setting themselves up for an easy stun, every single time! They literally click, and sign up to be out of the fight for 3-5 seconds (depending on length of the portal and you getting the stun off). Now, I understand that this advantage probably applies mostly to the players I'm coming up against in normal solo queue, but nonetheless, I think it may be worth noting. The thing is, abilities that are so multi-use, such as Magical Journey, have so many different ways of being effective, and have greater tactical & strategic advantages than just showing up and ganking with your team. Baiting, distracting, even just opening a portal in an area where you know they are, without even going through it, can make an opponent flee. Thinking outside the box with Magical Journey, I think solo queue Bard can be great even without a coordinated team over voice chat.
I think people also try too hard with the ult. In a fight, just ulting the ADC or a tower from the get-go and allowing your team to position around them is huge. That alone has won a large percentage of fights. I'm really surprised that Riot implemented this ultimate, though. Used from a place of panic or uncertainty is I think the problem. Players who play Bard might benefit from outlining specific circumstances where they blow the ult, so that they avoid throwing the game with a single toss of an ability.
Anyway, just my own thoughts on some of what I've observed. I think he's fun and I don't feel like a waste of space on teams, generally. I'm not some masterful Bard player or anything and there's plenty of room to grow, but I feel like I've got a decent handle to carry my weight on a team without them playing around me.