I don't think just because Draven wasn't used in the tournament means he is bad. I main Draven alongside Graves when I play ADC and he is actually really fun to play. He deals tons of damage ( joke intended ) while denying champions escape if you're good at chaining your W with your Q. He is, however, really hard to play and you need focus when playing him, since you gotta catch his axes. He can also be shut down really hard by stuns, slows, exhaust, pretty much any forms of CC. That's why you will usually take cleanse over ignite on Draven, to counter that weakness a bit since your passive is already a form of ignite.
For the OP, i think you're trying to decide on a ADC, and I think Ezreal, Graves, and Vayne are some of the strongest ADC's right now. Caitlyn and Draven are also good picks. Go with Ezreal since he is cheaper right now and I think much easier to play than Draven.