Bard is fine as a support. His laning is inferior to most other traditional supports, but it is made up for with his ability to roam. The main reason I think you see Bard as such a "bad" champion is because he has a bigger margin for error compared to all other champions. Since Bard can roam a lot because of his mobility, if he roams at a bad time, his lane partner(ADC) gets punished. He is also encouraged to roam to pick up chimes to increase his passive. His Q is a conditional stun that if missed, will involve you taking a lot of damage, but if you land it, you can lock up two of your opponents. His ultimate is also the same way. If you land it on opposing champions, you can easily set up a wombo combo and kill them, but if you miss it, you gimp your team incredibly hard. He has extremes which is why he is disliked. Play him well and you are greatly rewarded, but if you play him badly, you might as well have just been AFK.