Well, in his younger days he was (and still is) a great knight. I could go into more detail if you'd like. The part where the show is at, no, he does not do stuff. BUT he does do A LOT of stuff later on. He's not a point of view character yet in terms if where the show is with the books.
Free Step Dodge
ninjaguy446
Brute
In that case I'll just be patient and wait for him to start getting his chance to shine. I figured with Darrio gone and now with Jora exiled (or de-exiled, depending on how you look at it), Barristan would get more to do, as one of Targaryan's few remaining advisers.